Lighting Rigs

DMA-04

3D Animation Block –IV: 3D Lighting & Rendering (Practical)

Odisha State Open University

3D Animation

This course has been developed with the support of the Commonwealth of Learning (COL). COL is an intergovernmental organisation created by Commonwealth Heads of Government to promote the development and sharing of open learning and distance education knowledge, resources and technologies. Odisha State Open University, Sambalpur (OSOU) is the first Open and Distance learning institution in the State of Odisha, where students can pursue their studies through Open and Distance Learning (ODL) methodologies. Degrees, Diplomas, or Certificates awarded by OSOU are treated as equivalent to the degrees, diplomas, or certificates awarded by other national universities in India by the University Grants Commission.

© 2018 by the Commonwealth of Learning and Odisha State Open University. Except where otherwise noted, 3D Animation is made available under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) License: https://creativecommons.org/licenses/by-sa/4.0/legalcode For the avoidance of doubt, by applying this license the Commonwealth of Learning does not waive any privileges or immunities from claims that it may be entitled to assert, nor does the Commonwealth of Learning submit itself to the jurisdiction, courts, legal processes or laws of any jurisdiction. The ideas and opinions expressed in this publication are those of the author/s; they are not necessarily those of Commonwealth of Learning and do not commit the organisation

Odisha State Open University Commonwealth of Learning

G.M. University Campus 4710 Kingsway, Suite 2500, Sambalpur Burnaby, V5H 4M2, British, Odisha Columbia India Canada Fax: +91-0663-252 17 00 Fax: +1 604 775 8210 E-mail: [email protected] Email: [email protected] Website: www.osou.ac.in Website: www.col.org

https://creativecommons.org/licenses/by-sa/4.0/legalcode

mailto:[email protected]

Acknowledgements The Odisha State Open University and COL, Canada wishes to thank those Resource Persons below for their contribution to this DMA-04:

Concept / Advisor

Dr. Srikant Mohapatra Vice- Chancellor Odisha State Open University, Sambalpur

Course Writer

A.C.Balaji Head, Department of Animation Manipal University

Course Editor

S.Anuradha Bangalore based Freelancer

Video Production

R. Mohana Sundaram Creative Director Jai Ram Institute of Visual Academy, Khurda, Odisha Guest Faculty, National Institute of Fashion Technology (NIFT), Bhubaneswar

Published by :

Dr. Jayanta Kar Sharma Registrar on behalf of Odisha State Open University, Sambalpur

Contribution of following staff members of Odisha State Open University is acknowledged:

Sambit Mishra

Debidatta Behera

Prashansa Das

Radhakanta Suna

Abhinandan Tripathy

OSOU and COL acknowledge the support extended by Prof. Madhu Parhar, STRIDE, IGNOU, New Delhi in conducting several workshops in the process of preparation of course material for DMA

3D Animation

Contents

Contents

Course overview 5

Welcome to3D Lighting& Rendering ............................................................................... 5

Introduction to Lighting .................................................................................................... 5 Understanding Shadows ................................................................................................... 6 Using lamps in Blender ..................................................................................................... 6 Using Light Rigs ............................................................................................................... 6 Course outcomes ............................................................................................................... 7

Timeframe ......................................................................................................................... 8 Study skills ........................................................................................................................ 8

Need help? ........................................................................................................................ 8 Assignments ...................................................................................................................... 9 Assessments ...................................................................................................................... 9 Video Resources .............................................................................................................. 9

Getting around this Course material 10

Margin icons ................................................................................................................... 10

Unit-1 11

Introduction to 3D Lighting ............................................................................................ 11 Introduction ........................................................................................................... 11 Outcomes ............................................................................................................... 11

Terminology .......................................................................................................... 11

Viewing Restrictions ............................................................................................. 12 Global Influences .................................................................................................. 13 Lighting Settings ................................................................................................... 13 Falloff Types ......................................................................................................... 18 Sphere .................................................................................................................... 25

Examples ............................................................................................................... 26 Lamps Textures ..................................................................................................... 30 Lamps Related Settings ......................................................................................... 31 Render Layers ........................................................................................................ 32

Unit summary ........................................................................................................ 33

Assessment ............................................................................................................ 34

Resources ............................................................................................................... 35

Unit 2 36

Introduction to Understanding Shadows ......................................................................... 36 Introduction ........................................................................................................... 36 Outcomes ............................................................................................................... 36

ii Contents

Terminology .......................................................................................................... 37

Terminology ......................................................................................................... 37 Lamps: Ray-traced Shadows ................................................................................. 37 Lamps: Buffered Shadows .................................................................................... 39 Indirect Lighting .................................................................................................... 41 Ambient Occlusion (AO) ...................................................................................... 43

Shadow Panel ........................................................................................................ 50 Volumetric Lighting .............................................................................................. 56

Unit summary ........................................................................................................ 57

Assignment ............................................................................................................ 57

Assessment ............................................................................................................ 57

Resources ............................................................................................................... 58

Unit 3 59

Using Lamps in Blender ................................................................................................. 59 Introduction ........................................................................................................... 59 Outcomes ............................................................................................................... 59

Terminology .......................................................................................................... 60 Lamp:Point ............................................................................................................ 60 Lamp: Sun ............................................................................................................. 62

Lamp: Sky & Atmosphere ..................................................................................... 64 Lamps: Spot ........................................................................................................... 66

Shadows ................................................................................................................. 68 Spot Shape ............................................................................................................. 69 Buffer Type ........................................................................................................... 71

Spot Volumetric Effects ........................................................................................ 79

Lamp: Hemi ........................................................................................................... 80 Lamp: Area ............................................................................................................ 82 Area Raytraced Shadows ....................................................................................... 84

Unit summary ........................................................................................................ 87

Assignment ............................................................................................................ 87

Assessment ............................................................................................................ 88

Unit 4 90

Using Light Rigs ............................................................................................................. 90 Introduction ........................................................................................................... 90

Outcomes ............................................................................................................... 90 Brief the Proc ......................................................................................................... 90

Terminology .......................................................................................................... 90 Lighting Rigs ......................................................................................................... 91 Troubleshooting ..................................................................................................... 99 Camera ................................................................................................................. 100 Camera Lens ........................................................................................................ 103

Lens Type ............................................................................................................ 103 Camera Preset ...................................................................................................... 108 Safe Areas ............................................................................................................ 112

3D Animation

Unit summary ...................................................................................................... 116

Assignment .......................................................................................................... 116

Assessment .......................................................................................................... 117

Resources ............................................................................................................. 117

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5

Course overview

Welcome to3D Lighting& Rendering

Lighting is a very important topic in Rendering, standing equal to modelling, materials and textures. The most accurately modelled and textured scene will yield poor results without a proper lighting scheme, while a simple model can become very realistic if skilfully lit.

Light would not even exist without its counterpart: Shadows. Shadows are a darkening of a portion of an object, because light is being partially or totally blocked from illuminating the object.

In this course, you will learn about Lighting using Lamps in Blender. A Shading model is used to describe how surfaces respond to light. Lighting refers to the simulation of light in computer graphics using Blender.

A rig is a standard setup and combination of objects; there can be lighting rigs, or armature rigs, etc. A rig provides a basic setup and allows you to start from a known point and go from there. Different rigs are used for different purposes and emulate different conditions; the rig you start with depends on what you want to convey in your scene.

In Block 1, Block 2 and Block 3, you have learnt about 3D Modelling, 3D Shading and 3D Animation and Rigging respectively. Now In this Block 4, you will learn about 3D Lighting and Rendering.

Introduction to Lighting

Lighting is a very important topic in Rendering, standing equal to modelling, materials and textures. The most accurately modelled and textured scene will yield poor results without a proper lighting scheme, while a simple model can become very realistic if skilfully lit.Lighting plays key role in 3D Animation, because it convinces the audience that the story is believable psychological and physical of lighting emphasizes the role of lighting on the audience “light dictates activities, influences our frame of mind and affects the way we perceive all manner of things”. In this Unit

Course overview Introduction to 3D Lighting

6

1, you will learn to create your 3D Scene for Lighting; Identify the restrictions between the color of an object and the lighting of your scene; Design global influences affecting the lighting in the scene; Practice setting up the lights and how to Apply texture maps to lamp color channels.

Understanding Shadows

Light would not even exist without its counterpart: Shadows. Shadows are a darkening of a portion of an object, because light is being partially or totally blocked from illuminating the object. They add contrast and volume to a scene; there is nearly no place in the real world without shadows, so to get realistic renders, you will need them. Blender supports the various kinds of shadows: Lamps: Ray-traced Shadows; Lamps: Buffered Shadows; Ambient Occlusion and Indirect Lighting. In this course, you will learn about Shadows; the various kinds of Shadows; and how to work on Direct and Indirect Lighting.

Using lamps in Blender

In this Unit, you will learn about Lighting using Lamps in Blender. A Shading model is used to describe how surfaces respond to light. Lighting refers to the simulation of light in computer graphics using Blender. In this Unit, you will learn how to Design lighting with relevant Lamp type; Differentiate the Lamp types with its Options; Apply Lamp options for the available light setup and shadow parameters in Blender software; Create illumination using Lamps in Blender; Work on different setups created for diverse needs of your 3D Scene and to Work on Dome type of lighting called Hemi and Area Lighting to create the desired effects on the objects using Lamps in Blender.

Using Light Rigs

A rig is a standard setup and combination of objects; there can be lighting rigs, or armature rigs, etc. A rig provides a basic setup and allows you to start from a known point and go from there. Different rigs are used for different purposes and emulate different conditions; the rig you start with depends on what you want to convey in your scene. Lighting can be very confusing, and

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the defaults do not give good results. Further, very small changes can have a dramatic effect on the mood and colors. In this Unit, you will learn how to Design One-point, Two-point and Three-point light rigs; Utilize Camera Setup for Final rendering; Recall all the lighting parameters to create one final Light Rig; Practice Lighting for different light setups Home, Factory, Office, Indoor, outdoor etc.; Use Lighting Rig to produce photorealistic results with its physically plausible shading and lighting system; Work with lights realistically, with shape and falloff; and to Produce final quality results, resulting in faster setup and more accurate results.

This video will provide a brief overview of this course.

Topic YouTube link QR

Code

Video 1 –Lights &Camera

https://youtu.be/yAM6c4U

LpgA

Course outcomes

Upon completion of 3D Lighting and Rendering you will be able to:

Outcomes

Plan your 3D Scene for Lighting

Apply texture maps to lamp color channels

Compose lighting with relevant shadow type

Differentiate the types of shadows

Design lighting with relevant Lamp type

Differentiate the Lamp types with its Options

Design One-point, Two-point and Three-point light rigs

Utilize Camera Setup for Final rendering

https://youtu.be/yAM6c4ULpgA

https://youtu.be/yAM6c4ULpgA

Course overview Introduction to 3D Lighting

8

Timeframe

How long?

This course will be completed within “2” classes.

This course is of “1” credits.

1 Hour of study time is required for this unit.

Study skills

This is a totally practical oriented course.

Hence, you should have access to personal computer or personal laptop for better understanding of this unit.

Each and every options are explained step by step in the course material.

Apart from this course material, the learner has to adopt the tendency of learning from multiple sources i.e.,

Internet tutorials

Video tutorials on YouTube

Collaboration with people working in the industry etc.

Only classroom study will not make you a professional. You have to be active to grab the opportunity of learning wherever you get a chance.

Need help?

Help

In case of any help needed you can browse the internet sites like youtube.com for video tutorials about the subject.

Apart from that, you can contact the writer of this course material at [email protected]

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Assignments

Assignments

There will be some assignments at the end of each unit.

These assignments are mostly practical based and should be submitted in CD or DVD. Theoretical assignments are to be submitted neatly written on A4 size sheet.

All assignments will be submitted to Regional centre of Odisha State Open University or as directed by Co-ordinator.

All assignment should be unit wise on separate CD/DVDs clearly mentioning course title and unit on Top. Theoretical Assignment will be neatly filed or spiral bind with cover clearly mentioning necessary information of course, student detain on top.

Assessments

Assessments

There will be few assessment questions for each unit.

All practical assessment will be submitted to OSOU.

Assessment will take place once at the end of each unit.

Learner will be allowed to complete the assessment within stipulated time frame given by the university.

Video Resources

This study material comes with additional online resources in the form of

videos. As videos puts in human element to e-learning at the same time

demonstrating the concepts visually also improves the overall learning

experience.

You can download any QR code reader from Google Play to view the

videos embedded in the course or type the URL on a web browser.

Reading

Getting around this Course material Introduction to 3D Lighting

10

Getting around this Course material

Margin icons

While working through this Course material you will notice the frequent use of margin icons. These icons serve to “signpost” a particular piece of text, a new task or change in activity; they have been included to help you to find your way around thisCourse material.

A complete icon set is shown below. We suggest that you familiarize yourself with the icons and their meaning before starting your study.

Activity Assessment Assignment Case study

Discussion Group activity Help Note it!

Outcomes Reading Reflection Study skills

Summary Terminology Time Tip

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Unit-1

Introduction to 3D Lighting

Introduction


Lighting plays key role in 3D Animation, because it convinces the audience that the story is believable psychological and physical of lighting emphasizes the role of lighting on the audience “light dictates activities, influences our frame of mind and affects the way we perceive all manner of things”.

Outcomes

Upon completion of this unit you will be able to:

Outcomes

Plan your 3D Scene for Lighting

Identify the restrictions between the color of an object and the lighting of your scene

Design global influences affecting the lighting in the scene

Practice setting up the lights

Apply texture maps to lamp color channels

Terminology

Terminology

Ambient Light: Ambient light means the light that is already present in a scene, before any additional lighting is added. It usually refers to natural light, either outdoors or coming through windows etc. It can also mean artificial lights such as normal room lights.

Ambient Ambient occlusion is a method to approximate how bright light should be shining on any





A rig is a standard setup and combination of objects; there can be lighting rigs, or armature rigs, etc. A rig provides a basic setup and allows you to start from a known point and go from there. Different rigs are used

Unit-1 Introduction to 3D Lighting

12

Occlusion: specific part of a surface, based on the light and its environment. This is used to add realism

Indirect Lighting:

Lighting provided by reflection usually from wall or ceiling surfaces. In day lighting, this means that the light coming from the sky or the sun is reflected on a surface of high reflectivity like a wall, a window sill or a special redirecting device. In electrical lighting, the luminaries are suspended from the ceiling or wall mounted and distribute light mainly upwards so it gets reflected off the ceiling or the walls

Direct Lighting:

Direct sunlight is when you (or the plant) get the rays directly on it. It is like sitting outside, without a hat, and nothing is between you and the sun.

Viewing Restrictions

The Color of an object and the lighting of your scene are affected by:

Your ability to see different colors (partial color blindness

is common).

The medium in which you are viewing the image (e.g. an

LCD panel versus printed glossy paper).

The quality of the image (e.g. a jpeg at 0.4 compression

versus 1.0).

The environment in which you are viewing the image (e.g.

a CRT monitor with glare versus in a dark room, or in a

sunshiny blue room).

Your brain’s perception of the color and intensity relative to those objects around it and the world background color, which can be changed using color manipulation techniques using Blender Composite Nodes.

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Global Influences

In Blender, the elements under your control which affect lighting are:

The color of the world ambient light.

The use of Ambient Occlusion to cast that ambient light

onto the object.

The degree to which the ambient light colors the material

of the object.

The use of Indirect lighting, where the color of one object

radiates onto another.

The lamps in your scene.

The physics of light bouncing around in the real world is

simulated by Ambient Occlusion (a world setting), buffer

shadows (which approximate shadows being cast by

objects), ray tracing (which traces the path of photons

from a light source).

Also, within Blender you can use Indirect lighting. Ray tracing, Ambient Occlusion, and Indirect Lighting are computer-intensive processes. Blender can perform much faster rendering with its internal scan line renderer, which is a very good scan line renderer indeed. This kind of rendering engine is much faster since it does not try to simulate the real behavior of light, assuming many simplifying hypotheses.

Lighting Settings

Only after the above global influences have been considered, do you start adding light from lamps in your scene. The main things under your control are the:

Type of light used (Sun, Spot, Lamp, Hemi, etc.).

Color of the light.

Position of the light and its direction.

Settings for the light, including energy and falloff.

Then you are back to how that material’s Shader reacts to the light.


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This Unit attempts to address the above, including how lights can work together in rigs to light your scene. In this Unit, we will analyze the different type of lights in Blender and their behavior; we will discuss their strong and weak points. We will also describe many lighting rigs, including the ever-popular three-point light method.

Lighting in the Workflow

In this Unit, you should set up your lighting before assigning materials to your meshes. Since the material Shaders react to light, without proper lighting, the material Shaders will not look right, and you will end up fighting the Shaders, when it is really the bad lighting that is causing you grief. All the example images in this Unit do not use any material setting at all on the ball, cube or background.

Overriding Materialsto Reset Lighting

Title-Img 1. 1Material field in the Render Layers panel.

Attribution-

Source-

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/introduct

ion.html?highlight=overriding%20materials%20reset%20lighting

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/introduction.html?highlight=overriding%20materials%20reset%20lighting

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/introduction.html?highlight=overriding%20materials%20reset%20lighting

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If you have started down the road of assigning materials, and are now fiddling with the lighting, we suggest that you

Step 1: create a default, generic gray material – no

Vertex Color, no Face Texture, no Shadeless, just

plain old middle gray with RGB (0.8, 0.8, 0.8).

Step 2: Name this “Gray”.

Step 3: Next go to the Render Layer tab.

Step 4: In the Layer panel, select your new “Gray”

material in the Material field. This will override any

materials you may have set, and render everything

with this color. Using this material, you can now go

about adjusting the lighting.

Step 5: Just empty this field to get back to your original

materials.

Lamp Panel

Title-Img 1. 2Lamp tab.

Attribution-

Source-


16

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/la

mp_panel.html

Lamp

A Data-Block Menu. Its list shows all light settings used in

the current scene.

Texture Count

Shows the count of textures in the lamp texture stack.

Preview

A quick preview of the light settings.

Lamp Type

Types of lamps available in Blender Internal. They share all or some of the options listed here:

Color

The color of the light source’s illumination.

Energy

The intensity of the light source’s illumination from (0.0 to

10.0).

Distance

The Distance number button indicates the number of

Blender Units (BU) at which the intensity of the current

light source will be half of its intensity. Objects less than

the number of BU away from the lamp will get more light,

while objects further away will receive less light. Certain

settings and lamp falloff types affect how the Distance is

interpreted, meaning that it will not always react the same.

The Sun and Hemi Lamps are another class of Lamps which

uses a constant falloff. Those lamps do not have a Distance

parameter, and are often called “Base Lighting Lamps”.

Influence

Every lamp has a set of switches that control which objects

receive its light, and how it interacts with materials.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/lamp_panel.html

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/lamp_panel.html

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Negative

Let the lamp cast negative light. The light produced by the

lamp is subtracted from the irradiance on the surfaces it

hits, which darkens these surfaces instead of brightening

them.

This Layer Only

The Lamp only illuminates objects on the same layer the

lamp is on. Causes the lamp to only light objects on the

same layer.

Specular

The Lamp creates specular highlights.

Diffuse

The Lamp affects diffuse shading.

Light Attenutation

Title-Img 1. 3Lamp panel, falloff options highlighted.

Attribution-

Source-

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/att

enuation.html

There are two main controls for light falloff for Point and Spot lamps:

1. The lamp Fallofftype selector

2. The Spherecheckbox

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/attenuation.html



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Falloff Types

Lin/Quad Weighted

Title-Img 1. 4 Lamp panel with Lin/Quad Weighted Falloff options

highlighted.

Attribution-

Source-blender.org

Link-


enuation.html

When this setting is chosen, two sliders are shown, Linearand Quadratic, which control respectively the “linearness” and “quadraticness” of the falloff curve.

This lamp falloff type is in effect allowing the mixing of the two light attenuation profiles (linear and quadratic attenuation types).

Quadratic Attenuation

Title-Img 1. 5 Lamp with Lin/Quad Weighted falloff default settings.

Attribution-



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Source-blender.org

Link-


enuation.html

This slider input field can have a value between (0.0 to 1.0). A value of 1.0 in the Quadratic field and 0.0 in the Linear field means that the light from this source is completely quadratic.

Quadratic Attenuation type lighting is considered a more accurate representation of how light attenuates (in the real world). In fact, fully quadratic attenuation is selected by default. For Lin/Quad Weighted lamp fallout. Here again, the light intensity is half when it reaches the Distance value from the lamp. Comparing the quadratic falloff to the linear falloff, the intensity decays much slower at distances lower than the set Distance, however, it attenuates much quicker after Distance is reached.

Zeroing both “Linear” and “Quad”

If both the Linear and Quadratic sliders have 0.0 as their values, the light intensity will not attenuate with distance. This does not mean that the light will not get darker, rather it will, however, only because the energy the light has is spread out over a wider and wider distance. The total amount of energy in the spread-out light will remain the same, though. The light angle also affects the amount of light you see. It is in fact the behavior of light in the deep space vacuum.

If you want a light source that does not attenuate and gives the same amount of light intensity to each area it hits, you need a light with properties like the Constant lamp Falloff type.

Also, when the Linear and Quad sliders are both 0.0 values the Distance field ceases to have any influence on the light attenuation, as shown by the equation above.

Graphical Summary

Below is a Graph Summarizing the lin/quad attenuation type, showing attenuation with or without the Sphere option (described later).




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Title-Img 1. 6 Lin/quad attenuation type

Attribution-

Source-blender.org

Link-


enuation.html

Light Attenuation:

Linear (Linear=1.0, Quad=0.0);

Quadratic (Linear=0.0, Quad=1.0);

Linear and quadratic (Linear=Quad=0.5);

Null (Linear=Quad=0.0);

Also, shown in the graph the “same” curves, in the same colors, however, with the Sphere button turned on.

Custom Curve

The Custom Curve Lamp Falloff type is very flexible.

Most other lamp falloff types work by having their light intensity start at its maximum (when nearest to the light source) and then with some predetermined pattern decrease their light intensity when the distance from the light source increases.

When using the Custom Curve Lamp Falloff type, a new panel is created called Falloff Curve. This Falloff Curve profile graph allows the user to alter how intense light is at a particular point along a light’s attenuation profile (i.e. at a specific distance from the light source).

The Falloff Curve profile graph has two axes, the Distance-axis and the Intensity-axis.



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1. Distance axis

It represents the position at a particular point along a light

source’s attenuation path. The far left is at the position of

the light source and the far right is the place where the

light source’s influence would normally be completely

attenuated.

2. Intensity axis

It represents the intensity at a particular point along a light

source’s attenuation path. Higher intensity is represented

by being higher up the intensity axis, while lower intensity

light is represented by being lower down on the intensity

axis.

Altering the Falloff Curve profile graph is easy. Just LMB click on a

part of the graph you want to alter and drag it where you want it to be. If you click over or near one of the tiny black square handles, it will turn white, indicating that this handle is now selected, and you will be able to drag it to a new position. If when you click on the graph you are not near a handle, one will be created at the point that you clicked, which you can then drag where you wish. You can also create handles at specific parts of

the graph, clicking with LMB while holding Ctrl ; it will create a

new handle at the point you have clicked.

In the example below (the default for the Falloff Curve Profile Graph), the graph shows that the intensity of the light starts off at its maximum (when near the light), and linearly attenuates as it moves to the right (further away from the light source).

Default Falloff Curve panel

graph. Render showing the Custom Curve lamp falloff type effect with default settings.

Title-Img 1. 7 Falloff Curve Profile Graph


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Attribution-

Source-blender.org

Link-


enuation.html

If you want to have a light attenuation profile that gets more intense as it moves away from the light source, you could alter the graph as below:

Falloff Curve for reversed

attenuation.

Falloff Curve for reversed attenuation rendered.

Title-Img 1. 8Falloff Curve Profile Graph

Attribution-

Source-blender.org

Link-


enuation.html

You are obviously not just limited to simple changes such as reversing the attenuation profile, you can have almost any profile you desire.

Here is another example of a different Falloff Curve profile graph, along with its resultant render output:





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Oscillating attenuation profile.

Render showing the effects of a “wavelet”

profile graph on the light attenuation.

Title-Img 1. 9 Falloff Curve Profile Graph

Attribution-

Source-blender.org

Link-


enuation.html

Inverse Square

Title-Img 1. 10 Render showing the Inverse Square lamp falloff type effect with

default settings.

Attribution-

Source-blender.org

Link-


enuation.html






24

This lamp falloff type attenuates its intensity according to inverse square law, scaled by the Distance value. Inverse square is a sharper, realistic decay, useful for lighting such as desk lamps and street lights. This is similar to the old Quad option (and consequently, to the new Lin/Quad Weighted option with Linear to 0.0 and Quad to 1.0), with slight changes.

Inverse Linear

Title-Img 1.11Render showing the Inverse Linear lamp falloff type effect with

default settings.

Attribution-

Source-blender.org

Link-


enuation.html

This lamp falloff type attenuates its intensity linearly, scaled by the Distance value. This is the default setting, behaving the same as the default in previous Blender versions without Quad switched on, and consequently, like the new Lin/Quad Weighted option with Linear to 1.0 and Quad to 0.0. This is not physically accurate, however, can be easier to light with.

Constant

Title-Img 1.12Render showing the Constant lamp falloff type effect with default settings.



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Attribution- Source-blender.org

Link-


enuation.html

This lamp falloff type does not attenuate its intensity with distance. This is useful for distant light sources like the sun or sky, which are so far away that their falloff is not noticeable. Sun and Hemi lamps always have constant falloff.

Such a falloff model is commonly used in real-time rendering applications via a shading language like GLSL.

Sphere

Title-Img 1. 6Screenshot of the 3D View editor, showing the Sphere light clipping

circle.


Link-


enuation.html

The Sphere option restricts the light illumination range of a Lamp or Spot lamp, so that it will completely stop illuminating an area once it reaches the number of Blender Units away from the Lamp, as specified in the Distance field.

When the Sphere option is active, a dotted sphere will appear around the light source, indicating the demarcation point at which this light intensity will be null.






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Render showing the light attenuation of

a Constant falloff light type with the Sphere option active.

Render showing the light attenuation of

a Constant falloff light type with the Sphere option deactivated.

Title-Img 1. 7Lin/Quad Weighted attenuation option.


Link-


enuation.html

Examples

Distance Example

In this example, the Lamp has been set pretty close to the group of planes. This causes the light to affect the front, middle and rear planes more dramatically. Looking at Img 1.15 below, you can see that as the Distance is increased, more and more objects become progressively brighter.

Distance: 10.

Distance: 100.

Distance: 1000.

Title-Img 1. 8 Various Distance settings (shadows disabled).


Link-


enuation.html





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The Distance parameter is controlling where the light is falling – at a linear rate by default – to half its original value from the light’s origin. As you increase or decrease this value, you are changing where this half falloff occurs. You could think of Distance as the surface of a sphere and the surface is where the light’s intensity has fallen to half its strength in all directions. Note that the light’s intensity continues to fall even after Distance. Distance just specifies the distance where half of the light’s energy has weakened.

Notice in Img 1.15 Distance: 1000., that the farthest objects are very bright. This is because the falloff has been extended far into the distance, which means the light is very strong when it hits the last few objects. It is not until 1000 Units that the light’s intensity has fallen to half of its original intensity.

Contrast this with Img 1.15 Distance: 100., where the falloff occurs so soon that the farther objects are barely lit. The light’s intensity has fallen by a half by time it even reaches the tenth object.

You may be wondering why the first few planes appear to be dimmer? This is because the surface angle between the light and the object’s surface normal is getting close to oblique. That is the nature of a Lamp light object. By moving the light infinitely far away you would begin to approach the characteristics of the Sun lamp type.

Inverse Square Example

Inverse Square makes the light’s intensity falloff with a non-linear rate, or specifically, a quadratic rate. The characteristic feature of using Inverse Square is that the light’s intensity begins to fall off very slowly however, then starts falling off very rapidly. We can see this in Img. 1.16 Inverse Square selected. (with the specified distances). images.

Inverse Square with 10.

Inverse Square with 100.

Inverse Square with

1000.

Title-Img 1. 9 Inverse Square selected. (with the specified distances).

Attribution-


28

Source-blender.org

Link-


enuation.html

With Inverse Square selected, the Distance field specifies where the light begins to fall off faster, roughly speaking; see the light attenuation description in Falloff types for more info.

In Img. 1.16 Inverse Square with 10., the light’s intensity has fallen so quickly that the last few objects are not even lit.

Both Img. 1.16 Inverse Square with 100. and Img. 1.16 Inverse Square with 1000. appear to be almost identical and that is because the Distance is set beyond the farthest object’s distance which is at about 40 BU out. Hence, all the objects get almost the full intensity of the light.

As above, the first few objects are dimmer than farther objects because they are very close to the light. Remember, the brightness of an object’s surface is also based on the angle between the surface normal of an object and the ray of light coming from the lamp.

This means there are at least two things that are controlling the surface’s brightness: intensity and the angle between the light source and the surface’s normal.

Sphere Example

Title-Img 1. 10Clipping Sphere.


Link-


enuation.html





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29

Sphere indicates that the light’s intensity is null at the Distance and beyond, regardless of the chosen light’s falloff. In Img 1.17 Clipping Sphere. you can see a side view example of the setup with Sphere enabled and a distance of 10.

Any object beyond the sphere receive no light from the lamp.

The Distance field is now specifying both where the light’s rays become null, and the intensity’s ratio falloff setting. Note that there is no abrupt transition at the sphere: the light attenuation is progressive (for more details, see the descriptions of the Sphere and Falloff types above).

Sphere with 10.

Sphere with 20.

Sphere with 40.

Title-Img 1. 11 Sphere enabled with the specified distances, Inverse Linear light

falloff.


Link-


enuation.html

In Img 1.18 Sphere with 10., the clipping sphere’s radius is 10 Units, which means the light’s intensity is also being controlled by 10 Units of distance. With a linear attenuation, the light’s intensity has fallen very low even before it gets to the first object.

In Img 1.18 Sphere with 20., the clipping sphere’s radius is now 20 BU and some light is reaching the middle objects.

In Img 1.18 Sphere with 40., the clipping sphere’s radius is now 40 Units, which is beyond the last object. However, the light does not make it to the last few objects because the intensity has fallen to nearly 0.




30

Lamps Textures

Title-Img 1. 12Lamp Texture panels.


Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/te

xtures.html

When a new lamp is added, it produces light in a uniform, flat color. While this might be sufficient in simple renderings, more sophisticated effects can be accomplished through the use of textures. Subtle textures can add visual nuance to a lamp, while hard textures can be used to simulate more pronounced effects, such as a disco ball, dappled sunlight breaking through treetops, or even a projector. These textures are assigned to one of ten channels, and behave exactly like material textures, except that they affect a lamp’s color and intensity, rather than a material’s surface characteristics.

Options

The lamp textures settings are grouped into two panels. Here we will only talk about the few things that differ from object material textures.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/textures.html

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/textures.html

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31

Study Skills

Refer “DMA-04, Block 02 3D Shading, Unit 01 - Materials and Shader” for details about the standard options.

The Texture-specific and the Mapping panels remain the same. However, you will note there are much fewer Mapping options. You can only choose between Global, View or another Object ‘s texture coordinates (since a lamp has no texture coordinates by itself), and you can scale or offset the texture.

The Mapping panel is also a subset of its regular material’s counterpart. You can only map a lamp texture to its regular, basic Color and/or to its Shadow color. As you can only affect colors, and a lamp has no texture coordinates on its own, the Diffuse, Specular, Shading, and Geometry options have disappeared.

Lamps Related Settings

Here are some options closely related to light sources, without being lamps settings.

Lighting Groups:

Materials

Title-Img 1. 13Light Group options for Materials.


Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/in_

other_contexts.html

By default, materials are lit by all lamps in all visible layers, however, a material (and thus all objects using that material) can be limited to a single group of lamps. This sort of control can be

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/in_other_contexts.html



32

incredibly useful, especially in scenes with complex lighting setups. To enable this, navigate to the Material menu’s Options panel and select a group of lamps in the Light Group field. Note that a light group must be created first.

If the Exclusive button is enabled, lights in the specified group will only affect objects with this material.

Render Layers

Title-Img 1. 14Light Group options for Render Layers.


Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lights/in_

other_contexts.html

There is a similar control located in the Layer panel of the Render Layers tab. If a light group name is selected in this Light field, the scene will be lit exclusively by lamps in the specified group.



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33

Unit summary

Summary

In this Unit, you have learnt what is 3D Lighting and how to

Plan your 3D scene for lighting

View limitations and global influences to setup a perfect

lighting angle for your 3D Assets

Set up the lights using Lamp Panel controlling light intensity

with the help of curve, attenuation.

Produce subtle visual nuance using texture connecting with

channels

After learning this Unit, you can download the Open Source Software available on the internet for free of cost to practice the possibilities of creating 3D Interface.

Assignment

Assignment

Students are expected to experiment the lighting setups and parameters available in the panel.

https://www.blender.org/download/




34

Assessment

Assessment

1. Define Indirect Lighting

2. Write a note on Lamp Panel

3. Describe Light Attenuation

4. Describe Sphere Option in Lighting

Write down the steps to create Lamp Texturing

Fill in the Blanks

1. ______________ means the light that is already present in

a scene.

2. Direct lighting is equal to __________ Light.

3. Lamp only illuminates objects on the _________ when the

lamp is on.

4. There are two main controls for light falloff - Point

and____________.

5. The _______________ option restricts the light illumination range of a Lamp or Spot lamp

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35

Resources

Study skills

While studying this Unit, you can browse the internet links for online video tutorials and several books and training DVDs available in theBlender Storeand on theBlender Cloud.

wiki.blender.org

ia600207.us.archive.org

archive.org

www.blender.org

docs.blender.org

https://store.blender.org/

https://cloud.blender.org/

http://www.blender.org/

Unit 2 Introduction to Understanding Shadows

36

Unit 2

Introduction to Understanding Shadows

Introduction

Light would not even exist without its counterpart: Shadows. Shadows are a darkening of a portion of an object, because light is being partially or totally blocked from illuminating the object. They add contrast and volume to a scene; there is nearly no place in the real world without shadows, so to get realistic renders, you will need them. Blender supports the following kinds of shadows:

1. Lamps: Ray-traced Shadows

2. Lamps: Buffered Shadows

3. Ambient Occlusion

4. Indirect Lighting

In this Unit, you will learn about Shadows and the various kinds of Shadows.

Outcomes


Outcomes

Compose lighting with relevant shadow type

Differentiate the types of shadows

Apply shadow options for the available light setup in Blender software

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37

Terminology

Lamps: Ray-traced Shadows

Ambient Occlusion really is not a shadow based on light per se, however, based on geometry. However, it does mimic an effect where light is prevented from fully and uniformly illuminating an object, so it is mentioned here. Also, it is important to mention Ambient Lighting, since increasing Ambient decreases the effect of a shadow.

You can use a combination of ray-traced and Buffer Shadows to achieve different results. Even within ray-traced shadows, different lamps cast different patterns and intensities of shadow. Depending on how you arrange your lamps, one lamp may wipe out or override the shadow cast by another lamp.

Shadows are one of those trifectas in Blender, where multiple things must be set up in different areas to get results:

The Lamp must cast shadows (ability and direction).

Terminology

Raytrace: In computer graphics, ray tracing is a technique for generating an image by tracing the path of light through pixels in an image plane and simulating the effects of its encounters with virtual objects, such as reflection and refraction, scattering, and dispersion phenomena

Ambient Occlusion:

Ambient occlusion is a method to approximate how bright light should be shining on any specific part of a surface, based on the light and its environment. This is used to add realism.

Attenuation: Length of rays defines how far away other faces

may be and still have an occlusion effect. The

longer this distance, the greater impact that far-

away geometry will have on the occlusion

effect.

Chains of Bones: Bone can be the parent of several children, and

hence be part of several chains at the same

time.


38

An Opaque object must block light on its way (position and

layer).

Another object’s material must receive shadows (Shadow

and Receive Transparent enabled).

The render engine must calculate shadows (Shadow for

buffered shadows, Shadow and Ray for ray-traced

shadows).

For example, the simple Lamp, Area, and Sun light have the ability to cast ray shadows, however, not Buffer Shadows. The Spot light can cast both, whereas the Hemi light does not cast any. If a Sun lamp is pointing sideways, it will not cast a shadow from a sphere above a plane onto the plane, since the light is not traveling that way. All lamps able to cast shadows share some common options, described in the Shadow Panel.

Just to give you more shadow options (and further confuse the issue), lamps and materials can be set to respectively only cast and receive shadows, and not light the diffuse/specular aspects of the object. Also, render layers can turn on/off the shadow pass, and their output may or may not contain shadow information.

Title-Img 2. 1Ray Shadow enabled for a lamp.

Attribution-

Source-blender.org

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/shadow

s/introduction.html?highlight=ray%20shadow%20enabled%20lamp

Ray-traced shadows produce very precise shadows with very low memory use, however, at the cost of processing time. This type of shadowing is available to all lamp types except Hemi.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/shadows/introduction.html?highlight=ray%20shadow%20enabled%20lamp


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39

As opposed to buffered shadows (Lamps: Buffered Shadows), ray-traced shadows are obtained by casting rays from a regular light source, uniformly and in all directions. The ray-tracer then records which pixel of the final image is hit by a ray light, and which is not. Those that are not are obviously obscured by a shadow.

Each light casts rays in a different way. For example, a Spot light casts rays uniformly in all directions within a cone. The Sun light casts rays from an infinitely distant point, with all ray’s parallel to the direction of the Sun light.

For each additional light added to the scene, with ray-tracing enabled, the rendering time increases. Ray-traced shadows require more computation than buffered shadows however, produce sharp shadow borders with very less memory resource usage.

To enable Ray-traced shadows, three actions are required:

Step 1: Enable Shadows globally in the Render Menu’s

Shading panel.

Step 2: Enable Ray tracing globally from the same panel.

Step 3: Enable ray-traced shadows for the light using the

Ray Shadow button in the Light menu’s Shadow panel.

This panel varies depending on the type of light.

All lamps able to cast ray-traced shadows share some common options, described in Ray-traced Properties.

Ray-traced shadows can be cast by the following types of lamp:

1. Point lamp

2. Spot lamp

3. Area lamp

4. Sun lamp

Lamps: Buffered Shadows


40

Title-Img 2. 2Buffer Shadow enabled for a Spot lamp.

Attribution-

Source- blender.org

Link-



Title-Img 2. 3Cast Buffer Shadows enabled for a material.

Attribution-

Source- blender.org

Link-



Buffered shadows provide fast-rendered shadows at the expense of precision and/or quality. Buffered shadows also require more memory resources as compared to ray tracing. You must use buffered shadows depending on your requirements. If you are rendering animations or cannot wait hours to render a complex scene with soft shadows, Buffer Shadows are a good choice.

For a scanline renderer – and Blender’s built-in engine is, among other things, a scanline renderer – shadows can be computed using a shadow buffer. This implies that an “image”, as seen from





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41

the spot lamp’s point of view, is “rendered” and that the distance – in the image – for each point from the spot light is saved. Any point in the “rendered” image that is farther away than any of those points in the spot light’s image is then considered to be in shadow. The shadow buffer stores this image data.

To enable buffered shadows these actions are required:

Step 1: Enable shadows globally from the Scene Menu’s

Gather panel by selecting Approximate.

Step 2: Enable shadows for the light using the Buffer

Shadow button in the Lamp menu’s Shadow panel.

Step 3: Make sure the Cast Buffer Shadows options is

enabled in each Material ‘s Shadow panel.

The Spot lamp is the only lamp able to cast buffered shadows.

Indirect Lighting

Indirect Lighting adds indirect light bouncing of surrounding objects. It models the light that is reflected from other surfaces to the current surface. It is more comprehensive, more physically correct, and produces more realistic images. It is also more computationally expensive.

Title-Img 2. 4Indirect Lighting parameters

Attribution-

Source- blender.org


42

Link-



Options

Indirect Lighting Panel contains two options:

1. Factor

Defines how much surrounding objects contribute to light.

2. Bounces

Number of indirect diffuse light bounces.

Gather Panel contains settings for the indirect lighting quality. Note that these settings also apply to Environment Lighting and Ambient Occlusion.

Approximate

Title-Img 2. 5 The Indirect Lighting panel, Approximate method.

Attribution-

Source- blender.org

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/world/indirect_li

ghting.html

The Approximate method gives a much smoother result for the same amount of render time, however, as its name states, it is only an approximation of the Raytrace method, which implies it might produce some artifacts and it cannot use the sky’s texture as the base color.

This method seems to tend to “over-occlude” the results. You have two complementary options to reduce this problem:

Passes



https://docs.blender.org/manual/en/dev/render/blender_render/world/indirect_lighting.html

https://docs.blender.org/manual/en/dev/render/blender_render/world/indirect_lighting.html

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43

Set the number of pre-processing passes, between (0 to

10) passes. Keeping the pre-processing passes high will

increase render time, however, will also clear some

artifacts and over-occlusions.

Error

This is the tolerance factor for approximation error (i.e. the

max allowed difference between approximated result and

fully computed result). The lower, the slower the render,

however, the more accurate the results... Ranges between

(0.0 to 10.0), defaults to 0.250.

Pixel Cache

When enabled, it will keep values of computed pixels to

interpolate it with its neighbors. These further speeds up

the render, generally without visible loss in quality...

Correction

A correction factor is to reduce over-occlusion. Ranges

between (0.0 to 1.0) correction.

Ambient Occlusion (AO)

Ambient Occlusion is a sophisticated ray-tracing calculation which simulates soft global illumination shadows by faking darkness perceived in corners and at mesh intersections, creases, and cracks, where ambient light is occluded, or blocked.

There is no such thing as AO in real life; AO is a specific not-physically-accurate (but generally nice-looking) rendering trick. It basically samples a hemisphere around each point on the face, sees what proportion of that hemisphere is occluded by other geometry, and shades the pixel accordingly.

It has got nothing to do with light at all; it is purely a rendering trick that tends to look nice because generally in real life surfaces that are close together (like small cracks) will be darker than surfaces that do not have anything in front of them, because of shadows, dirt, etc.

The AO process, though, approximates this result; it is not simulating light bouncing around or going through things. That is why AO still works when you do not have any lights in the scene, and it is why just switching on AO alone is a very bad way of “lighting” a scene.


44

You must have ray tracing enabled as a Render panel option in the Shading section for this to work.

You must have an ambient light color set as you desire. By default, the ambient light color (world) is black, simulating midnight in the basement during a power outage. Applying that color as ambient will actually darken all colors. A good outdoor mid-day color is RGB (0.9, 0.9, 0.8) which is a whitish yellow sunny kind of color on a bright-but-not-harshly-bright day.

Options

Title-Img 2. 6 The World panel with ambient color sliders highlighted.

Attribution-

Source- blender.org

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/world/ambient_

occlusion.html?highlight=world%20panel%20ambient%20color%20sliders%20highl

ighted

Factor

The strength of the AO effect, a multiplier for addition.

Ambient Occlusion is composited during the render. Two blending modes are available:

I. Add

The pixel receives light according to the number of non-

obstructed rays. The scene is lighter. This simulates global

illumination.

II. Multiply

Ambient occlusion is multiplied over the shading, making

things darker.

https://docs.blender.org/manual/en/dev/render/blender_render/world/ambient_occlusion.html?highlight=world%20panel%20ambient%20color%20sliders%20highlighted



3D Animation

45

Tip

If Multiply is chosen, there must be other light sources; otherwise the scene will be pitch black. In the other two cases, the scene is lit even if no explicit light is present, just from the AO effect. Although many people like to use AO alone as a quick shortcut to light a scene, the results it gives will be muted and flat, like an overcast day. In most cases, it is best to light a scene properly with Blender’s standard lamps, then use AO on top of that, set to Multiply, for the additional details and contact shadows.

The Gather panel contains settings for the ambient occlusion quality. Note that these settings also apply to Environment Lighting and Indirect Lighting.

Ambient occlusion has two main methods of calculation:

I. Raytrace and

II. Approximate

Gather

Gather Panel contains settings for the Ambient occlusion quality. Note that these settings also apply to Environment Lighting and Ambient Occlusion.

Raytrace

Title-Img 2. 7 The Amb Occ panel, Raytrace method.

Attribution-

Source- blender.org

Link-



ighted





46

The Raytrace method gives the more accurate, however, also the more noisy results. You can get a nearly noiseless image, however, at the cost of render time... It is the only option if you want to use the colors of your sky’s texture.

Attenuation

Length of rays defines how far away other faces may be and still have an occlusion effect. The longer this distance, the greater impact that far-away geometry will have on the occlusion effect. A high Distance value also means that the renderer must search a greater area for geometry that occludes, so render time can be optimized by making this distance as short as possible for the visual effect that you want.

Sampling Method

Constant QMC

The base Quasi-Monte Carlo, gives evenly and randomly distributed rays.

Adaptive QMC

An improved method of QMC, that tries to determine when the sample rate can be lowered or the sample skipped, based on its two settings:

Threshold

The limit below which the sample is considered fully occluded (“black”) or un-occluded (“white”), and skipped.

Adapt to Speed

A factor to reduce AO sampling on fast-moving pixels. As it

uses the Vector render pass, that must also be enabled.

Constant Jittered

The historical sample method, more prone to “bias”

artifacts...

Bias

The angle (in radians) the hemisphere will be made

narrower (i.e. the hemisphere will no longer be a real

hemisphere: its section will no longer be a semicircle,

however, an arc of a circle of: pi - bias radians).

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47

The bias setting allows you to control how smooth

“smooth” faces will appear in AO rendering. Since AO

occurs on the original faceted mesh, it is possible that the

AO light makes faces visible even on objects with “smooth”

on. This is due to the way AO rays are shot, and can be

controlled with the Bias slider. Note that while it might

even happen with QMC sampling methods, it is much more

visible with the Constant Jittered one and anyway, you

have no Bias option for QMC.

24×24 UV Sphere with Bias: 0.05 (default). Note the facets on the

sphere’s surface even though it is set to smooth.

Raising the Bias to 0.15 removes

the faceted artifacts.

Title-Img 2.8 Bias

Attribution-

Source- blender.org

Link-



ighted

Samples

The number of rays used to detect if an object is occluded. Higher numbers of samples give smoother and more accurate results, at the expense of slower render times. The default value of 5 is usually good for previews. The actual number of rays shot out is the square of this number (i.e. Samples at 5 means 25 rays). Rays are shot at the hemisphere according to a random pattern (determined by the sample methods described above); this causes differences in the occlusion pattern of neighboring pixels unless the number of shot rays is big enough to produce good statistical data.





48

Ambient Occlusion

with 3 Samples.

Ambient Occlusion

with 6 Samples.

Ambient Occlusion with 12 Samples.

Title-Img 2.9 Ambient Occlusion samples

Attribution-

Source- blender.org

Link-



ighted

Approximate

Title-Img 2.10 Ambient Occlusion panels,approximate method

Attribution-

Source- blender.org

Link-



ighted

The Approximate method gives a much smoother result for the same amount of render time, however, as its name states, it is only an approximation of the Raytrace method, which implies it might produce some artifacts and it cannot use the sky’s texture as the base color.

This method seems to tend to “over-occlude” the results. You have two complementary options to reduce this problem:

Passes

Set the number of pre-processing passes, between (0 to

10) passes. Keeping the pre-processing passes high will







3D Animation

49

increase render time however, will also clear some artifacts

and over-occlusions.

Error

This is the tolerance factor for approximation error (i.e. the

max allowed difference between approximated result and

fully computed result). The lower, the slower the render,

however, the more accurate the results... Ranges between

(0.0 to 10.0), defaults to 0.250.

Pixel Cache

When enabled, it will keep values of computed pixels to

interpolate it with its neighbours.This further speed up the

render, generally without visible loss in quality...

Correction

A correction factor to reduce over-occlusion. Ranges

between (0.0 to 1.0) correction.

Common Settings

Falloff

When activated, the distance to the occluding objects will

influence the “depth” of the shadow. This means that the

further away the occluding geometry is, the lighter its

“shadow” will be. This effect only occurs when the

Strength factor is higher than 0.0. It mimics light dispersion

in the atmosphere...

Strength

Controls the attenuation of the shadows enabled with Use

Falloff. Higher values give a shorter shadow, as it falls off

more quickly (corresponding to a more foggy/dusty

atmosphere). Ranges from (0.0 to 10.0), default is 0.0,

which means no falloff.

Technical Details

Ambient occlusion is calculated by casting rays from each

visible point, and by counting how many of them actually

reach the sky, and how many, on the other hand, are

obstructed by objects.


50

The amount of light on the point is then proportional to

the number of rays which have “escaped” and have

reached the sky. This is done by firing a hemisphere of

shadow rays around. If a ray hits another face (it is

occluded) then that ray is considered “shadow”, otherwise

it is considered “light”. The ratio between “shadow” and

“light” rays defines how bright a given pixel is.

Tip

Ambient Occlusion is a ray-tracing technique (at least with the Raytrace method), so it tends to be slow. Furthermore, performance severely depends

on octree size.

Shadow Panel

Title-Img 2.11 Common shadowing options for lamps.

Attribution-

Source- blender.org

Link-


s/shadow_panel.html?highlight=common%20shadowing%20options%20lamps

All lamps able to cast shadows. Share some options, described below:

Shadow Method

No Shadow

The lamp casts no shadow.

Buffered Shadow

The Spot lamp is the only lamp able to cast buffered

shadows.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/shadows/shadow_panel.html?highlight=common%20shadowing%20options%20lamps


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51

Raytraced Shadows

Ray-traced Properties.

This Layer Only

When this option is enabled, only the objects on the same

layer as the light source will cast shadows.

Only Shadow

The light source will not illuminate an object however, will

generate the shadows that would normally appear. This

feature is often used to control how and where shadows

fall by having a light which illuminates however, has no

shadow, combined with a second light which does not

illuminate however, has Only Shadow enabled, allowing

the user to control shadow placement by moving the

“Shadow Only” light around.

Shadow color

This color picker control allows you to choose the color of

your cast shadows (black by default). The images below

were all rendered with a white light and the shadow color

was selected independently.

Red colored shadow

example.

Green colored

shadow example.

Blue colored shadow

example.

Title-Img 2.12 Shadow color

Attribution-

Source- blender.org

Link-


s/shadow_panel.html?highlight=common%20shadowing%20options%20lamps

Although you can select a pure white color for a shadow color, it appears to make a shadow disappear.




52

Raytraced Shadows

Title-Img 2.13 Ray shadowing options for lamps.

Attribution-

Source-blender.org

Link-


s/raytraced_properties.html

Most lamp types (Lamp, Spot and Sun) share the same options for the ray-

traced shadows generation, which are described below. Note that the

Area lamp, even though using most of these options, have some specifics

described in its own ray-traced shadows page.

Ray Shadow

The Ray Shadow button enables the light source to generate ray-traced shadows. When the Ray Shadow button is selected, another set of options is made available, those options being:

Shadow sample generator type

Method for generating shadow samples:

Adaptive QMC is fastest,

Constant QMC is less noisy however, slower. This

allows you to choose which algorithm is to be used

to generate the samples that will serve to compute

the ray-traced shadows

Constant QMC

The Constant QMC method is used to calculate shadow

values in a very uniform, evenly distributed way. This

method results in very good calculation of shadow value

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/shadows/raytraced_properties.html


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53

however, it is not as fast as using the Adaptive QMC

method; however, Constant QMC is more accurate.

Adaptive QMC

The Adaptive QMC method is used to calculate shadow

values in a slightly less uniform and distributed way. This

method results in good calculation of shadow value

however, not as good as Constant QMC. The advantage of

using Adaptive QMC is that it is in general much quicker

while being not much worse than Constant QMC in terms

of overall results.

Samples

Number of extra samples taken (samples x samples). This

slider sets the maximum number of samples that both

Constant QMC and Adaptive QMC will use to do their

shadow calculations. The maximum value is 16: the real

number of samples is actually the square of it, so setting a

sample value of 3 really means 32 = 9 samples will be

taken.

Soft Size

Light size for ray shadow sampling. This slider determines

the size of the fuzzy/diffuse/penumbra area around the

edge of a shadow. Soft Size only determines the width of

the soft shadow size, not how graded and smooth the

shadow is. If you want a wide shadow which is also soft

and finely graded, you must also set the number of

samples in the Samples field higher than 1; otherwise this

field has no visible effect and the shadows generated will

not have a soft edge. The maximum value for Soft Size is

100.0.

Below is a table of renders with different Soft Size and Samples settings showing the effect of various values on the softness of shadow edges:


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Soft Size: 1.0, Samples: 2.









Title-Img 2.14 Different soft size and samples

Attribution-

Source-blender.org

Link-



Below is an animated version of the above table of images showing the effects.



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Title-Img 2.15 Animated version renders with different Soft Size and

Samples settings showing the effect of various values on the softness of

shadow edges.

Attribution-

Source-blender.org

Link-



Threshold

Threshold is for Adaptive Sampling. This field is used with the Adaptive QMC shadow calculation method. The value is used to determine if the Adaptive QMC shadow sample calculation can be skipped based on a threshold of how shadowed an area is already. The maximum Threshold value is 1.0.

Quasi-Monte Carlo method

The Monte Carlo method is a method of taking a series of samples/readings of values (any kind of values, such as light values, color values, reflective states) in or around an area at random, so as to determine the correct actions to take in certain calculations which usually require multiple sample values to determine overall accuracy of those calculations. The Monte Carlo method tries to be as random as possible; this can often cause areas that are being sampled to have large irregular gaps in them (places that are not sampled/read). This in turn can cause problems for certain calculations (such as shadow calculation).

The solution to this was the Quasi-Monte Carlo method.

The Quasi-Monte Carlo method is also random, however, tries to make sure that the samples/readings it takes are also better




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distributed (leaving less irregular gaps in its sample areas) and more evenly spread across an area. This has the advantage of sometimes leading to more accurate calculations based on samples/reading.

Volumetric Lighting

Volumetric lighting is a technique used in 3D computer graphics to add lighting effects to a rendered scene. It allows the viewer to see beams of light shining through the environment; seeing sunbeams streaming through an open window is an example of volumetric lighting, also known as God rays. The term seems to have been introduced from cinematography and is now widely applied to 3D modeling and rendering especially in the field of 3D gaming. In volumetric lighting, the light cone emitted by a light source is modeled as a transparent object and considered as a container of a “volume”: as a result, light has the capability to give the effect of passing through an actual three dimensional medium (such as fog, dust, smoke, or steam) that is inside its volume, just like in the real world.”

—According to Wikipedia, Volumetric Lighting.

A classic example is the search light with a visible halo/shaft of light being emitted from it as the search light sweeps around.

By default, Blender does not model this aspect of light. For example, when Blender lights something with a Spot light, you see the objects and area on the floor lit however, not the shaft/halo of light coming from the spotlight as it progresses to its target and would get scattered on the way.

The halo/shaft of light is caused in the real world by light being scattered by particles in the air, some of which get diverted into your eye and that you perceive as a halo/shaft of light. The scattering of light from a source can be simulated in Blender using various options, however, by default is not activated.

The only lamp able to create volumetric effects is the Spot lamp (even thought you might consider some of the “Sky & Atmosphere” effects of the Sun lamp as volumetric as well).

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Unit summary

Summary

In this Unit, you have learnt

Create depth using Shadows and lights

Work on different types of shadows based on needs of

your 3D Scene

Work on Direct and Indirect Lighting

Work on Shadows using ambient occlusion and shadow passes.

After learning this Unit, you can download the Open Source

Software available on the internet for free of cost to practice the

possibilities of creating 3D Objects.

Assignment

Assignment

Use the same Living Room scene created for Block 02, Unit –

01 Assignment to light with Blender.

Use this key word “photo frame on wall” on

www.google.com to collect the reference image to build your

lighting reference.

Assessment

Assessment

1. Describe Ambient Occlusion

2. Write a note on Indirect Lighting

3. Define Volumetric Lighting

4. Write few lines about Raytracing

5. List the types of Shadow Settings available in Blender




http://www.google.com/

Resources

58

Fill in the Blanks

1. Ray-traced shadows produce very precise _____________ with very low memory.

2. ___________ shadows provide fast-rendered shadows.

3. Indirect Lighting adds light ________ of surrounding objects.

4. ____________ simulates soft global illumination shadows.

5. ____________ is also known as God rays.

Resources

Study Skills

While studying this Unit, you can browse the internet links for online video tutorials and several books and training DVDs available in theBlender Storeand on theBlender Cloud.

Links to download 3D Files for practice - Copyright Notice Attribution-Non Commercial – Share Alike CC BY-NC-SA

1. https://wiki.blender.org/index.php/Doc:2.4/Tutorials/Lighting/BSoD

2. https://cloud.blender.org/p/hdri

3. wiki.blender.org

4. ia600207.us.archive.org

5. archive.org

6. www.blender.org

7. docs.blender.org

Books to refer

8. Blender 2.5 Lighting and Rendering

9. https://www.lifewire.com/quick-tips-for-interesting-cg-lighting-2119









https://wiki.blender.org/index.php/Doc:2.4/Tutorials/Lighting/BSoD

https://cloud.blender.org/p/hdri


https://cloud.blender.org/p/textures/

https://www.lifewire.com/quick-tips-for-interesting-cg-lighting-2119


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Unit 3

Using Lamps in Blender

Introduction

In this Unit, you will learn about Lighting using Lamps in Blender. A Shading model is used to describe how surfaces respond to light.

Lighting refers to the simulation of light in computer graphics using Blender. This simulation can either be extremely accurate, as is the case in an application like Radiance which attempts to track the energy flow of light interacting with materials using Radiosity computational techniques. Alternatively, the simulation can simply be inspired by light physics, as is the case with non-photorealistic rendering. Between these two extremes, there are many different lighting approaches which can be employed to achieve almost on any desired visual result.

Outcomes


Outcomes

Design lighting with relevant Lamp type

Differentiate the Lamp types with its Options

Apply Lamp options for the available light setup and shadow parameters in Blender software

Unit 3 Using Lamps in Blender

60

Terminology

Terminology

Turbidity: Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.

Light Falloff: A candle across the room illuminates your book less well than a candle at your shoulder. The decline in illumination with distance is called falloff or attenuation and in a physics

Volumetric Lighting: Volumetric lighting is a technique used in 3D computer graphics to add lighting effects to a rendered scene.

Lamp:Point

Title-Img 3. 1Point lamp

Atribution-

Source- docs.blender.org

Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/p

oint.html

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/point.html


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The Point lamp is an omni-directional point of light, that is, a point radiating the same amount of light in all directions. It’s visualized by a plain, circled dot. Being a point light source, the direction of the light hitting an object’s surface is determined by the line joining the lamp and the point on the surface of the object itself.

Light intensity/energy decays based on (among other variables) distance from the Point lamp to the object. In other words, surfaces that are further away are rendered darker.

Shadows

Title-Img 3. 2Without ray shadows.

Atribution-


Link-


oint.html

Title-Img 3. 3 Point lamp with ray shadows and Adaptive QMC sample

generator enabled.

Atribution-


Link-


oint.html

The Point light source can only cast ray-traced shadows. It shares with other lamp types the common shadow options described in Shadow Panel.

The ray-traced shadows settings of this lamp are shared with other lamps, and are described Raytraced Properties.






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Lamp: Sun

A Sun lamp provides light of constant intensity emitted in a single direction. A Sun lamp can be very handy for a uniform clear daylight open-space illumination. In the 3D View, the Sun light is represented by an encircled black dot with rays emitting from it, plus a dashed line indicating the direction of the light.

This direction can be changed by rotating the Sun lamp, like any other object, but because the light is emitted in a constant direction, the location of a Sun lamp does not affect the rendered result (unless you use the “sky & atmosphere” option).

Title-Img 3. 4Sun lamp panel.

Atribution-


Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/s

un/introduction.html

Lamp options

Energy and Color

These settings are common to most types of lamps, and

are described in Light Properties.

Negative, This Layer Only, Specular, and Diffuse

These settings control what the lamp affects, as described

in What Light Affects.

The Sun lamp has no light falloff settings: it always uses a constant attenuation (i.e. no attenuation!).

Sky & Atmosphere

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/sun/introduction.html


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Title-Img 3. 5Sky & Atmosphere panel.

Atribution-


Link-



Various settings for the appearance of the sun in the sky, and the atmosphere through which it shines, are available.

Shadow

Title-Img 3. 6Shadow panel.

Atribution-

Source-

Link-








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The Sun light source can only cast ray-traced shadows. It shares with other lamp types the same common shadowing options, described in Shadow Panel.

The ray-traced shadows settings of this lamp are shared with other lamps, and are described in Raytraced Properties.

Lamp: Sky & Atmosphere

Title-Img 3. 7Sky & Atmosphere panel.

Atribution-

Source-

Link-



This panel allows you to enable an effect that simulates various properties of real sky and atmosphere: the scattering of sunlight as it crosses the kilometers of air overhead. For example, when the Sun is high, the sky is blue (and the horizon, somewhat whitish). When the Sun is near the horizon, the sky is dark blue/purple, and the horizon turns orange. The dispersion of the atmosphere is also more visible when it is a bit foggy: the farther away an object is, the more “faded” in light gray it is... Go out into the countryside on a nice hot day, and you will see it.



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To enable this effect, you have to use a Sun light source. If, as usual, the position of the lamp has no importance, its rotation is crucial: it determines which hour it is. As a starting point, you should reset rotation of your Sun (with Alt-R, or typing 0 in each of the three Rotation Fields X, Y, Z in the Transform panel). This way, you will have a nice mid-day sun (in the tropics).

Now, there are two important angles for the Sky/Atmosphere effect: the “incidence” angle (between the light direction and the X-Y plane), which determines the “hour” of the day (as you might expect, the default rotation – straight down – is “mid-day”, a light pointing straight up is “midnight”, and so on...). And the rotation around the Z axis determines the position of the sun around the camera.

Title-Img 3. 8 The dashed “light line” of the Sun lamp crossing the camera

focal point.

Atribution-


Link-


un/sky_atmosphere.html

In fact, to have a good idea of where the sun is in your world, relative to the camera in your 3D View, you should always try to have the dashed “light line” of the lamp crossing the center of the camera (its “focal” point), as shown in Img 3. 8(The dashed “light line” of the Sun lamp crossing the camera focal point). This way, in camera view (Numpad0, center area in the example picture), you will see where the “virtual” sun created by this effect will be.

It is important to understand that the position of the sun has no importance for the effect: only its orientation is relevant. The position just might help you in your scene design.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/sun/sky_atmosphere.html



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Distance: 3.0.

Distance: 4.0.

Title-Img 3. 9 Variations in Distance parameter, all other settings to default.

Atribution-


Link-


un/sky_atmosphere.html

Hints and limitations

To always have the Sun pointing at the camera center, you can use a Track To constraint on the sun object, with the camera as target, and -Z as the “To” axis (use either X or Y as “Up” axis). This way, to modify height/position of the sun in the rendered picture, you just have to move it; orientation is automatically handled by the constraint. Of course, if your camera itself is moving, you should also add e.g. a Copy Location constraint to your Sun lamp, with the camera as target and the Offset option activated... This way, the sun light will not change as the camera moves around.

If you use the default Add mixing type, you should use a very dark-blue world color, to get correct “nights”...

This effect works quite well with a Hemi lamp, or some ambient occlusion, to fill in the Sun shadows.

Atmosphere shading currently works incorrectly in reflections and refractions and is only supported for solid shaded surfaces. This will be addressed in a later release.

Lamps: Spot

A Spot lamp emits a cone-shaped beam of light from the tip of the cone, in a given direction.

The Spot light is the most complex of the light objects and indeed, for a long time, among the most used thanks to the fact that it was the only one able to cast shadows. Nowadays, with a ray tracer



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integrated into Blender’s internal render engine, all lamps can cast shadows (except Hemi). Even so, Spot lamps’ shadow buffers are much faster to render than ray-traced shadows, especially when blurred/softened, and spot lamps also provide other functionality such as “volumetric” halos.

Lamp options

Title-Img 3. 9Common Lamp options of a Spot.

Atribution-


Link-


pot/introduction.html?highlight=common%20lamp%20options%20spot

Distance, Energy and Color



This Layer Only, Negative, Diffuse and Specular



Light Falloff and Sphere

These settings control how the light of the Spot decays

with distance.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/spot/introduction.html?highlight=common%20lamp%20options%20spot



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Title-Img 3. 10 Changing the Spot options also changes the appearance of

the spotlight as displayed in the 3D View.

Atribution-


Link-



Shadows

Title-Img 3. 11Shadow panel set to Ray Shadow.

Atribution-


Link-



Spotlights can use either ray-traced shadows or buffered shadows. Either of the two can provide various extra options. Ray-traced shadows are generally more accurate, with extra





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capabilities such as transparent shadows, although they are quite slower to render.

No Shadow

Choose this to turn shadows off for this spot lamp. This can

be useful to add some discreet directed light to a scene.

Buffer Shadow

Buffered Shadows are also known as depth map shadows.

Shadows are created by calculating differences in the

distance from the light to scene objects. Buffered shadows

are more complex to set up and involve more faking, but

the speed of rendering is a definite advantage.

Nevertheless, it shares with other lamp types common

shadow options described in Shadow Panel.

Ray Shadow

The ray-traced shadows settings of this lamp are shared

with other lamps, and are described in Raytraced

Properties.

Spot Shape

Size

The size of the outer cone of a Spot, which largely controls the circular area a Spot light covers. This slider in fact controls the angle at the top of the lighting cone, and can be between (1.0 to 180.0).

Title-Img 3. 12Changing the spot size option

Atribution-



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Link-



Blend

The Blend slider controls the inner cone of the Spot. The Blend value can be between (0.0 to 1.0). The value is proportional and represents that amount of space that the inner cone should occupy inside the outer cone Size.

The inner cone boundary line indicates the point at which light from the Spot will start to blur/soften; before this point its light will mostly be full strength. The larger the value of Blend the more blurred/soft the edges of the spotlight will be, and the smaller the inner cone’s circular area will be (as it starts to blur/soften earlier).

To make the Spot have a sharper falloff rate and therefore less blurred/soft edges, decrease the value of Blend. Setting Blend to 0.0 results in very sharp spotlight edges, without any transition between light and shadow.

The falloff rate of the Spot lamp light is a ratio between the Blend and Size values; the larger the circular gap between the two, the more gradual the light fades between Blend and Size.

Blend and Size only control the Spot light cone’s aperture and softness (“radial” falloff); they do not control the shadow’s softness as shown below (Img 3.14)

Title-Img 3. 13 Render showing the soft edge spotlighted area and the sharp/hard

object shadow.

Atribution-

Source-

Link-







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Notice in the picture above Img 3. 14that the object’s shadow is sharp as a result of the ray tracing, whereas the spotlight edges are soft. If you want other items to cast soft shadows within the Spot area, you will need to alter other shadow settings.

Square

The Square button makes a Spot light cast a square light

area, rather than the default circular one.

Show Cone

Draw a transparent cone in 3D View to visualize which

objects are contained in it.

Halo

Adds a volumetric effect to the spot lamp.

Spot Buffered Shadows

When the Buffer Shadow button is activated, the currently selected Spot light generates shadows, using a “shadow buffer” rather than using raytracing, and various extra options and buttons appear in the Shadow panel.

Buffer Type

There more than one way to generate buffered shadows. The shadow buffer generation type controls which generator to use.

There are four shadow generation types, those being:

1. Classical

2. Classic-Halfway

3. Irregular

4. Deep


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Title-Img 3. 14Buffer Shadow set to Classic-Halfway.

Atribution-

Source-

Link-


pot/buffered_shadow.html

Classical

A Classical shadow generation method, which is used to be the Blender default and unique method for generation of buffered shadows. It used an older way of generating buffered shadows, but it could have some problems with accuracy of the generated shadows and can be very sensitive to the resolution of the shadow

buffer Shadow Buffer ‣ Size, different Bias values, and all the self-shadowing issues that brings up.

The Classical method of generating shadows is obsolete and is really only still present to allow for backward compatibility with older versions of Blender. In most other cases, you will want to use Classic-Halfway instead.

Classic-Halfway

This shadow buffer type is an improved shadow buffering method and is the default option selected in Blender. It works by taking an averaged reading of the first and second nearest Z depth values allowing the Bias value to be lowered and yet not suffer as much from self-shadowing issues.

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/spot/buffered_shadow.html


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Not having to increase Bias values helps with shadow accuracy, because large Bias values can mean small faces can lose their shadows, as well as preventing shadows being overly offset from the larger Bias value.

Classic-Halfway does not work very well when faces overlap, and biasing problems can happen.

Options

Here are now the options specific to these generation methods:

Size

The Size number button can have a value from (512 to 10240).Size represents the resolution used to create a shadow map. This shadow map is then used to determine where shadows lay within a scene.

As an example, if you have a Size with a value of 1024, you are indicating that the shadow data will be written to a buffer which will have a square resolution of 1024×1024 pixels/samples from the selected spotlight.

The higher the value of Size, the higher resolution and accuracy of the resultant shadows, assuming all other properties of the light and scene are the same, although more memory and processing time would be used. The reverse is also true – if the Size value is lowered, the resultant shadows can be of lower quality, but would use less memory and take less processing time to calculate.

As well as the Size value affecting the quality of generated shadows, another property of Spot lamps that affects the quality of their buffered shadows is the angle of the spotlights lighted area (given in the Spot Shape Panel’s Size field).

As the spot shape Size value is increased, the quality of the cast shadows degrades. This happens because when the Spot lighted area is made larger (by increasing spot shape Size), the shadow buffer area must be stretched and scaled to fit the size of the new lighted area.

The Size resolution is not altered to compensate for the change in size of the spotlight, so the quality of the shadows degrades. If you want to keep the generated shadows the same quality, as you increase the spot shape Size value, you also need to increase the buffer Size value.


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Tip

The above basically boils down to

If you have a spotlight that is large you will need to have a larger buffer Size to keep the shadows good quality. The reverse is true also – the quality of the generated shadows will usually improve (up to a point) as the Spot lamp covers a smaller area.

Filter Type

The Box, Tent, and Gauss filter types control what filtering algorithm to use to anti-alias the buffered shadows.

They are closely related to the Samples number button, as when this setting is set to 1, shadow filtering is disabled, so none of these buttons will have any effect whatsoever.

Box

The buffered shadows will be anti-aliased using the “box” filtering method. This is the original filter used in Blender. It is relatively low quality and is used for low resolution renders, as it produces very sharp anti-aliasing. When this filter is used, it only takes into account oversampling data which falls within a single pixel, and does not take into account surrounding pixel samples. It is often useful for images which have sharply angled elements and horizontal/vertical lines.

Tent

The buffered shadows will be anti-aliased using the “tent” filtering method. It is a simple filter that gives sharp results, an excellent general-purpose filtering method. This filter also takes into account the sample values of neighboring pixels when calculating its final filtering value.

Gauss

The buffered shadows will be anti-aliased using the “Gaussian” filtering method. It produces a very soft/blurry anti-aliasing. As result, this filter is excellent with high resolution renders.

Samples

The Samples number button can have a value between (1 and 16). It controls the number of samples taken per pixel when calculating shadow maps.

The higher this value, the more filtered, smoothed and anti-aliased the shadows cast by the current lamp will be, but the longer they will take to calculate and the more memory they will use. The anti-

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aliasing method used is determined by having one of the Box, Tent or Gauss buttons activated.

Having a Samples value of 1 is similar to turning off anti-aliasing for buffered shadows.

Soft

The Soft number button can have a value between (1.0 to 100.0). It indicates how wide an area is sampled when doing anti-aliasing on buffered shadows. The larger the Soft value, the more graduated/soft the area that is anti-aliased/softened on the edge of generated shadows.

Sample Buffers

The Sample Buffers setting can be set to values (1, 4 or 9), and represents the number of shadow buffers that will be used when doing anti-aliasing on buffered shadows.

This option is used in special cases, like very small objects which move and need to generate really small shadows (such as strands). It appears that normally, pixel width shadows do not anti-alias properly, and that increasing Buffer Size does not help much.

So, this option allows you to have a sort of extra sample pass, done above the regular one (the one controlled by the Box / Tent / Gauss, Samples and Soft settings).

The default 1 value will disable this option.

Higher values will produce a smoother anti-aliasing – but be careful: using a Sample Buffers of 4 will require four times as much memory and process time, and so on, as Blender will have to compute that number of sample buffers.

Irregular

Title-Img 3. 15Buffer Shadow set to Irregular.


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Atribution-


Link-



Irregular shadow method is used to generate sharp/hard shadows that are placed as accurately as raytraced shadows. This method offers very good performance because it can be done as a multi-threaded process.

This method supports transparent shadows. To do so, you will first need to setup the shadow setting for the object which will receive

the transparent shadow Material ‣ Shadow ‣ Cat Buffer Shadows and Buffer Bias.

Deep Generation Method

Title-Img 3. 16Buffer Shadow set to Deep.

Atribution-


Link-



Deep Shadow buffer supports transparency and better filtering, at the cost of more memory usage and processing time.

Compress

Deep shadow map compression threshold.





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Common options

The following settings are common to all buffered shadow generation method.

Bias

The Bias number button can have a value between (0.001 to 5.0).Bias is used to add a slight offset distance between an object and the shadows cast by it. This is sometimes required because of inaccuracies in the calculation which determines whether an area of an object is in shadow or not.

Making the Bias value smaller results in the distance

between the object and its shadow being smaller. If the

Bias value is too small, an object can get artifacts, which

can appear as lines and interference patterns on objects.

This problem is usually called “self-shadowing”, and can

usually be fixed by increasing the Bias value, which exists

for that purpose!

Other methods for correcting self-shadowing include

increasing the size of the Shadow Buffer Size or using a

different buffer shadow calculation method such as

Classic-Halfway or Irregular.

Self-shadowing interference tends to affect curved

surfaces more than flat ones, meaning that if your scene

has a lot of curved surfaces it may be necessary to increase

the Bias value or Shadow Buffer Size value.

Having overly large Bias values not only places shadows

further away from their casting objects, but can also cause

objects that are very small to not cast any shadow at all. At

that point altering Bias, Shadow Buffer Size or Spot Size

values, among other things, may be required to fix the

problem.

Tip

Finer Bias tuning

You can now refine the Bias value independently for each Material, using the Bias slider (Material menu, Shadow panel). This value is a factor by which the Bias value of each Spot buffered shadows lamp is multiplied, each time its light hits an object using this


78

material. The (0.0 and 1.0) values are equivalent. They do not alter the lamp’s Bias original value.

Clip Start & Clip End

When a Spot light with buffered shadows is added to a

scene, an extra line appears on the Spot 3D View

representation.

The start point of the line represents Clip Start ‘s value and

the end of the line represents Clip End ‘s value. Clip Start

can have a value between (0.1 to 1000.0), and Clip End,

between (1.0 to 5000.0). Both values are represented in

Blender Units.

Clip Start indicates the point after which buffered shadows

can be present within the Spot light area. Any shadow

which could be present before this point is ignored and no

shadow will be generated.

Clip End indicates the point after which buffered shadows

will not be generated within the Spotlight area. Any

shadow which could be present after this point is ignored

and no shadow will be generated.

The area between Clip Start and Clip End will be capable of

having buffered shadows generated.

Altering the Clip Start and Clip End values helps in

controlling where shadows can be generated. Altering the

range between Clip Start and Clip End can help speed up

rendering, save memory and make the resultant shadows

more accurate.

When using a Spot lamp with buffered shadows, to

maintain or increase quality of generated shadows, it is

helpful to adjust the Clip Start and Clip End such that their

values closely bound around the areas which they want to

have shadows generated at. Minimizing the range between

Clip Start and Clip End, minimizes the area shadows are

computed in and therefore helps increase shadow quality

in the more restricted area.

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Autoclip Start & Autoclip End

As well as manually setting Clip Start and Clip Endfields to

control when buffered shadows start and end, it is also

possible to have Blender pick the best value independently

for each Clip Start and Clip End field.

Blender does this by looking at where the visible vertices

are when viewed from the Spot lamp position.

Hints

Any object in Blender can act as a camera in the 3D View. Hence you can select the Spot light and switch to a view from its perspective by pressing Ctrl-Numpad0.

Spot Volumetric Effects

Title-Img 3. 17Spot lamps’s Halo options.

Atribution-


Link-


pot/halo.html

Spot lights also can produce “volumetric” effects.

Halo

The Halo button allows a Spot lamp to have a volumetric

effect applied to it. This button must be active if the

volumetric effect is to be visible. Note that if you are using

buffered shadows.

Intensity

The Intensity slider controls how intense/dense the

volumetric effect is that is generated from the light source.

The lower the value of the Intensity slider, the less visible

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/spot/halo.html

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/spot/halo.html


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the volumetric effect is, while higher Intensity values give a

much more noticeable and dense volumetric effect.

Step

This field can have a value between (0 to 12). It is used to

determine whether this Spot will cast volumetric shadows,

and what quality those volumetric shadows will have. If

Step is set to a value of 0, then no volumetric shadow will

be generated. Unlike most other controls, asthe Step value

increases, the quality of volumetric shadows decreases

(but take less time to render), and vice versa.

Tip

Step values

A value of 8 for Halo Step is usually a good compromise

between speed and accuracy.

Blender only simulates volumetric lighting in Spot lamps when using its internal renderer. This can lead to some strange results for certain combinations of settings for the light’s Energy and the halo’s Intensity. For example, having a Spot light with null or very low light Energy settings but a very high halo Intensity setting can result in a dark/black halo, which would not happen in the real world. Just be aware of this possibility when using halos with the internal renderer.

Tip

The halo effect can be greatly enhanced when using buffered shadows: when the halo’s Step is not null, they can create “volumetric shadows”.

Lamp: Hemi

Title-Img 3. 18Hemi light conceptual scheme.

Atribution-

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Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/h

emi.html?highlight=hemi%20light%20conceptual%20scheme

The Hemi lamp provides light from the direction of a 180- hemisphere, designed to simulate the light coming from a heavily clouded or otherwise uniform sky. In other words, it is a light which is shed, uniformly, by a glowing dome surrounding the scene.

Similar to the Sun lamp, the Hemi ‘s location is unimportant, while its orientation is key.

The Hemi lamp is represented with four arcs, visualizing the orientation of the hemispherical dome, and a dashed line representing the direction in which the maximum energy is radiated, the inside of the hemisphere.

Options

Title-Img 3. 19Hemi lamp’s panel.

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Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/h

emi.html?highlight=hemi%20light%20conceptual%20scheme

Energy and Color

These settings are common to most types of lamps.

Layer, Negative, Specular, and Diffuse



The Hemi lamp has no light falloff settings: it always uses a constant attenuation (i.e. no attenuation).

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lamps/hemi.html?highlight=hemi%20light%20conceptual%20scheme





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Since this lamp is the only lamp which cannot cast any shadow, the Shadow panel is absent.

Lamp: Area

The Area lamp simulates light originating from a surface (or surface-like) emitter. For example, a TV screen, your supermarket’s neon lamps, a window, or a cloudy sky are just a few types of area lamp. The area lamp produces shadows with soft borders by sampling a lamp along a grid the size of which is defined by the user. This is in direct contrast to point-like artificial lights which produce sharp borders.

Title-Img 3. 20Commons Options.

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Link-http://blender-manual-

i18n.readthedocs.io/ja/latest/render/blender_render/lighting/lamps/area.html

Tip

Note that the Distance setting is much more sensitive and important for Area lamps than for others; usually any objects within the range of Distance will be blown out and overexposed. For best results, set the Distance to just below the distance to the object that you want to illuminate.

Lamp Options

Distance, Energy and Color



Gamma

Amount to gamma correct the brightness of illumination.

Higher values give more contrast and shorter falloff.

http://blender-manual-i18n.readthedocs.io/ja/latest/render/blender_render/lighting/lamps/area.html


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The Area lamp does not have light falloff settings. It uses

an “inverse quadratic” attenuation law. The only way to

control its falloff is to use the Distance and/or Gamma

settings.

This Layer Only, Negative, Specular and Diffuse

These settings control what the lamp affects.

Shadows

When an Area light source is selected, the Shadow panel has the following default layout:

Adaptive QMC settings.

Constant Jittered settings.

Title-Img 3. 21 The shadow panel when area light source is selected.

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Area Shape

The shape of the area light can be set to Square or Rectangle.

Square options.

Rectangle options.

Title-Img 3. 22Area shape

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Square / Rectangular

Emit light from either a square or a rectangular area






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Size / Size X / Size Y

Dimensions for the Square or Rectangle

Tip

Choosing the appropriate shape for your Area light will enhance the believability of your scene. For example, you may have an indoor scene and would like to simulate light entering through a window. You could place a Rectangular area lamp in a window (vertical) or from neons (horizontal) with proper ratios for Size X and Size Y. For the simulation of the light emitted by a TV screen a vertical Square area lamp would be better in most cases.

Area Raytraced Shadows

Title-Img 3. 23Adaptive QMC settings.

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The Area light source can only cast ray-traced shadows. The ray-traced shadows settings of this lamp are mostly shared with other lamps. However, there are some specifics with this lamp, which are detailed below:

Shadow Samples

Samples

This has the same role as with other lamps, but when using a Rectangle Area lamp, you have two samples settings: Samples X and Samples Y, for the two axes of the area plane. Note also that when using the Constant Jittered sample generator method, this is more or less equivalent to the number of virtual lamps in the



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area. With QMC sample generator methods, it behaves similarly to with Lamp or Spot lamps.

Sample Generator Types

Adaptive QMC / Constant QMC

These common setting are described in Shadow Panel.

Constant Jittered

The Area lamp has a third sample generator method,

Constant Jittered, which is more like simulating an array of

lights. It has the same options as the old one: Umbra,

Dither and Jitter.

Title-Img 3. 24Constant Jittered settings.

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The following three parameters are only available when using the Constant Jittered sample generator method, and are intended to artificially boost the “soft” shadow effect, with possible loss in quality:

Umbra

Umbra, emphasizes the intensity of shadows in the area

fully within the shadow rays. The light transition between

fully shadowed areas and fully lit areas changes more

quickly (i.e. a sharp shadow gradient). You need Samples

values equal to or greater than 2 to see any influence of

this button.

Dither




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Applies a sampling over the borders of the shadows,

similar to the way anti-aliasing is applied by the OSA button

on the borders of an object. It artificially softens the

borders of shadows; when Samples is set very low, you can

expect poor results, so Dither is better used with medium

Samples values. It is not useful at all with high Samples

values, as the borders will already appear soft.

Jitter

Jitter adds noise to break up the edges of solid shadow

samples, offsetting them from each other in a pseudo-

random way. Once again, this option is not very useful

when you use high Samples values where the drawback is

that noise generates quite visible graininess.

Hints

You will note that changing the Size parameter of your area lamp does not affect the lighting intensity of your scene. On the other hand, rescaling the lamp using the S in the 3D View could dramatically increase or decrease the lighting intensity of the scene. This behavior has been coded this way so that you can fine tune all your light settings and then decide to scale up (or down) the whole scene without suffering from a drastic change in the lighting intensity. If you only want to change the dimensions of your Area lamp, without messing with its lighting intensity, you are strongly encouraged to use the Size button(s) instead.

If your computer is not very fast, when using the Constant Jittered sample generator method, you could find it useful to set a low Samples value (like 2) and activate Umbra, Dither, and/or Jitterin order to simulate slightly softer shadows. However, these results will never be better than the same lighting with high Samples values.

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Unit summary

Summary

In this Unit, you have learnt how to

Create illumination using Lamps in Blender.

Use lights allowing various shadow option types.

Work on different setups created for diverse needs of your

3D Scene.

Work on Dome type of lighting called Hemi and Area Lighting to create the desired effects on the objects using Lamps in Blender.

After learning this Unit, you can download the Open Source Software available on the internet for free of cost to practice the possibilities of creating 3D Objects.

Assignment

Use the same Living Room scene created for Block 02, Unit

– 01 Assignment to light with Blender, improvise the same

using Lamps as required.

Use these key words “photo frame on wall” on www.google.com to collect the reference image to build your lighting references.






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Assessment

1. Explain Light Falloff

2. Write a note on Point Lamp

3. Write short note on the following

a. Sun

b. Sky & Atmosphere

4. Explain Buffer Shadow with Illustrations

5. Draw Soft Shadow Edge and Hard Shadow edge using “Sphere” as a reference point

Fill in the Blanks

1. _____________ is an omni-directional source of light

2. Spot is a ___________ source of light.

3. __________ is a source simulating light, as windows, neon, TV screens.

4. Hemi simulates a very wide and far away light source, like the________.

5. ____________ simulates a very far away and punctual light source, like the sun.

Resources

Study Skills

While studying this Unit, you can browse the following internet links

for online video tutorials and several books and training DVDs

available in theBlender Storeand on theBlender Cloud.

Links to download 3D Files for practice - Copyright Notice Attribution-Non Commercial-Share Alike CC BY-NC-SA

1. https://wiki.blender.org/index.php/Doc:2.4/Tutorials/Lighting/

BSoD

2. https://cloud.blender.org/p/hdri\

3. wiki.blender.org


5. archive.org





https://cloud.blender.org/p/hdri/

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6. www.blender.org

7. docs.blender.org

Books to refer

8. Blender 2.5 Lighting and Rendering by Aaron W. Powell

9. Read Chapter 7 of the John Blain "Complete Guide to Blender

Graphics" - Lighting and Cameras (pages 131-136)

10. https://www.lifewire.com/quick-tips-for-interesting-cg-

lighting-2119




Unit 4 Using Light Rigs

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Unit 4

Using Light Rigs

Introduction

In this Unit, you will learn about Light Rigs and how it is used. A rig is a standard setup and combination of objects; there can be lighting rigs, or armature rigs, etc. A rig provides a basic setup and allows you to start from a known point and go from there.

Different rigs are used for different purposes and emulate different conditions; the rig you start with depends on what you want to convey in your scene. Lighting can be very confusing, and the defaults do not give good results. Further, very small changes can have a dramatic effect on the mood and colors.

Outcomes


Outcomes

Design One-point, Two-point and Three-point light rigs

Utilize Camera Setup for Final rendering

Recall all the lighting parameters to create one final Light Rig

Practice Lighting for different light setups Home, Factory, Office, Indoor, outdoor etc.,

Brief the Proc

Terminology

Light Rigs: It is a collection of lights used to set up a simple light to effectively highlight and show off your modeled assets. This series of lessons will walk through the absolute basics of lighting for presentation. Showcasing your work is an essential part of being a Computer Graphic artist, and lighting is essential to showing off.

Lens: A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single





A rig is a standard setup and combination of objects; there can be lighting rigs, or armature rigs, etc. A rig provides a basic setup and allows you to start from a known point and go from there. Different rigs are used for different purposes and

Terminology

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piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis

Depth of Field: In optics, particularly as it relates to film and photography, depth of field (DOF), also called focus range or effective focus range.

Lighting Rigs

In all the lighting rigs, the default camera is always positioned nearly 15 degrees off dead-on, about 25 BU (Blender Units) back and 9 BU to the side of the subject, at eye level, and uses a long lens of 80 mm. Up close, a 35 mm lens will distort the image. A long lens takes in more of the scene. A dead-on camera angle is too dramatic and frames too wide a scene to take in. So now you know; next time you go to a play, sit off-center and you will not miss the action happening on the sidelines and will have a greater appreciation for the depth of the set. Anyway, enough about camera angles; this is about lighting.

Environment or Ambient Light Only

Title-Img. 4. 1Environment (Ambient) lighting only.

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Link-

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lighting_

rigs.html

In the World tab, there is a panel Environment Lighting, where you enable environment or ambient lighting of your scene. Ambient light is the scattered light that comes from sunlight being reflected off every surface it hits, hitting your object, and traveling to camera.

Title-Img. 4. 2Ambient occlusion.

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rigs.html

Ambient light illuminates, in a perfectly balanced, Shadeless way, without casting shadows. You can vary the intensity of the ambient light across your scene via ambient occlusion. The ambient color is a sunny white.

Single Rig

https://docs.blender.org/manual/en/dev/render/blender_render/lighting/lighting_rigs.html




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Title-Img. 4. 3Standard Spot light rig.

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rigs.html

The sole, or key, spot light rig provides a dramatic, showy, yet effective illumination of one object or a few objects close together. It is a single Spot light, usually with a hard edge. Halos are enabled in this render to remind you of a smoky nightclub scene. It is placed above and directly in front of the subject; in this case 10 BU in front and 10 BU high, just like a stage, it shines down at about a 40 degrees angle. We use quadratic attenuation.

You can make the spot wider by increasing Size Spot Shape and softening the edge by increasing Blend Spot Shape, and parent it to the main actor, so that the spot follows him as he moves around. Objects close to the main actor will naturally be more lit and your viewer will pay attention to them.

Moving this spot directly overhead and pointing down gives the interrogation effect. At the opposite end of the show-off emotional spectrum is one soft candlelight (Point lamp, short falloff Distance, yellow light) placed really up close to the subject, dramatizing the fearful “lost in the darkness” effect.

Somewhere in the macabre spectrum is a hard spot on the floor shining upward. For fun, grab a flashlight, head into the bathroom and close the door. Turn out the light and hold the flashlight under your chin, pointing up. Look in the mirror and turn it on. From this




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you can see that lighting, even with a single light, varying the intensity, location and direction, changes everything in a scene.

Use this rig, with Environment Lighting (and props

receiving and being lit by ambient light in their material

settings) for scenes that feature one main actor or a

product being spotlighted.

Do not use this rig for big open spaces or to show all

aspects of a model.

Two-Point Rig

Title-Img. 4. 4Standard two-point light rig.

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rigs.html

The two-point lighting rig provides a balanced illumination of an object. Shown to the right are the views of the standard two-point lighting rig. It is called the two-point because there are two points of light. The standard two-point lighting rig provides a balanced illumination of untextured objects hanging out there in 3D space. This rig is used in real studios for lighting a product, especially a glossy one.

Both lights are almost the same but do different things. Both emulate very wide, soft light by being Hemi. In real life, these lights bounce light off the inside of a silver umbrella.

Notice how we use low Energy to bring out the dimensionality of the sphere; I cannot stress that enough. Hard, bright lights actually flatten it and make you squint. Soft lights allow your eye to focus.



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We disable specular for right Hemi, so we do not get that shiny forehead or nose.

The lamp on the left however, lets it be known that it is there by enabling specular; specular flare is that bright spot that is off center above midline on the sphere.

Use this rig to give even illumination of a scene, where

there is no main focus.

The Hemi‘s will light up background objects and props, so Environment Lighting is not that important. At the opposite end of the lighting spectrum, two narrow Spot lights at higher power with a hard edge give a “This is the Police, come out with your hands up” kind of look, as if the subject is caught in the crossfire.

Three-Point Rig

The standard three-point lighting rig is the most common illumination of objects and scenes bar none. If you want to show off your model, use this rig. As you can see, the untextured unmaterialized sphere seems to come out at you. There are multiple thesis on this rig, and you will use one of two:

1. Studio: Used in a real studio to film in front of a green

screen or backdrop. Use this rig when you are rendering

your CG objects to alpha into the scene so that the lighting

on the actors and your CG objects is the same.

2. Standard: Used in real life to light actors on a set, and gives

some backlighting to highlight the sides of actors, making

them stand out more and giving them depth.

Studio Rig

Title-Img. 4. 5Studio three-point light rig.

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rigs.html

Shown to the right are the “Studio” top, front, and side views of the standard three-point lighting rig. It changes the dynamics of the scene, by making a brighter “key” light give some highlights to the object, while two side “fill” lights soften the shadows created by the key light.

In the studio, use this rig to film a talking head (actor) in front of a green screen, or with multiple people, keeping the key light on the main actor. This rig is also used to light products from all angles, and the side fill lights light up the props.

The key light is the Area light placed slightly above and to the left of the camera. It allows the specular to come out. It is about 30 BU back from the subject, and travels with the camera. A little specular shine lets you know there is a light there, and that you are not looking at a ghost. In real life, it is a spot with baffles, or blinders, that limit the area of the light.

The two sidelights are reduced to only fill; each of them are Hemi lights placed 20 BU to the side and 5 BU in front of the subject, at ground level. They do not cause a spot shine on the surface by disabling specular, and at ground level, light under the chin or any horizontal surfaces, countering the shadows caused by the key light.

Use this rig to give balanced soft lighting that also

highlights your main actor or object.

It combines the best of both the single rig and the two-point rig, providing balanced illumination and frontal highlights. For a wide scene, you may have to pull the sidelights back to be more positioned like the two-point rig.

Standard Rig



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Title-Img. 4. 6Standard three-point light rig.

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rigs.html

Without a curtain in back of your main subject, you have depth to work with. The left fill light has been moved behind the subject (so it is now called a backlight) and is just off-camera, while the right-side fill light remains the same. The key light gives you specular reflection so you can play with specularity and hardness in your object’s material settings. The key light gives that “in-the-spotlight” feel, highlighting the subject, while the backlight gives a crisp edge to the subject against the background. This helps them stand out.

In this rig, the key light is a fairly bright spot light. Use a slighter tinge of yellow because the light is so bright; it is the only light for that side. The other sidelight has been moved in back and raised to eye (camera) level. You need to cut the energy of the backlight in half, or when it is added to the remaining sidelight, it will light up the side too much and call too much attention to itself. You can vary the angle and height of the backlight to mimic sun lighting up the objects.

Use this rig in normal 3D animations to light the main

actor.

Use this rig especially if you have transparent objects

(like glass) so that there is plenty of light to shine

through them to the camera.

The tricky part here is balancing the intensities of the lights so that no one light competes with or overpowers the others, while making sure all three works together as a team.




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Four-point Rig

Title-Img. 4. 7Four-point light rig.

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rigs.html

The four-point lighting rig provides a better simulation of outside lighting, by adding a Sun lamp 30 BU (Blender Unit) above, 10 to the side, and 15 BU behind the subject. This sunlight provides backlighting and fills the top of the subject; even producing an intentional glare on the top of their head, telling you there is a sun up there. Notice it is colored yellow, which balances out the blue sidelights.

Changing the key light to a Spot, select Inverse Square, disable Specularand pure white light combines with and softens the top sun flare while illuminating the face, resulting in a bright sunshine effect. Two lights above mean sharper shadows as well, so you might want to adjust the side fill lights. In this picture, they are still Hemi, disable Specular.

Use this rig when the camera will be filming from

behind the characters, looking over their shoulder or

whatnot, because the sun provides the backlight there.

Also use this rig when you have transparent objects, so

there is light to come through the objects to the

camera.

Another spot for the fill light is shining up onto the main actor’s face, illuminating the underside of his chin and neck. This gets rid



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of a sometimes-ugly shadow under the chin, which if not corrected, can make the actor look fat or like they have a double chin; otherwise distracting. It evens out the lighting of the face.

Troubleshooting

If you run into a problem with your render, where there are really bright areas, or really dark ones, or strange shadows, or lines on your objects, here are some good steps to debugging what is wrong:

First, try deactivating all materials (create a default,

gray one, and enter its name in the Mat field, Layer

panel, the Render Layer tab to get back all your normal

materials, just erase this text field!). See if you get

those problems with just grayness objects. If you do

not have the problem anymore, that should tell you

that you have got a materials-interacting-with-light

problem. Check the material settings, especially

ambient, reflection and all those little buttons and

sliders in the Material tab. You can set some lights to

affect only certain materials, so if there is an issue with

only a few objects being really bright, start with those.

Then start “killing” lights (e.g. moving them to an

unused layer); regress all the way back to one light,

make sure it is smooth, then add them in one by one.

As they add together, reduce power in the tested ones

so they merge cleanly, or consider not adding it at all,

or, especially, reduce the energy of the lamp you just

introduced.

You can also set lights to only light objects on a layer,

so again, if some of the gray spheres have weirdness,

check for that as well. Again, you may have done some

of this accidentally, so sometimes deleting the light and

re-adding it with defaults helps you reset to a known-

good situation.

Negative lights can be very tricky, and make your

model blotchy, so pay special attention to your use of

those special lights. Shadow-only lights can throw off

the look of the scene as well. Overly textured lights can

make your scene have random weird colors. Do not go

too far off a slight tinge of blue or yellow or shades of


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white, or your material may show blue in the Material

tab but render green, and you will be very confused.

Look at your Environment Settings World tab: Horizon, Zenith, and Environment Lighting.

Camera

A Camera is an object that provides a means of rendering images from Blender. It defines which portion of a scene is visible in the rendered image. By default, a scene contains one camera. However, a scene can contain more than one camera, but only one of them will be used at a time.

Add a New Camera

In Object mode simply press Shift-A and in the pop-up menu,

choose Add ‣ Camera.

The default scene in Blender includes a camera, so you’ll probably only need to add a new one if you have deleted the default one, or need to animate a cut between two cameras.

Changing the Active Camera

Reference

Mode: Object Mode

Hotkey: Ctrl-Numpad0

Title-Img. 4.

8Active camera (left one).

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Link-

https://docs.blender.org/manual/en/dev/render/blender_render/camera/introduc

tion.html

The Active Camera is the camera that is currently being used for rendering and camera view Numpad0.

Step 1: Select the camera you would like to make

active

Step 2: Press Ctrl-Numpad0

Step 3: Switch the view to camera view.

In order to render, each scene must have an active camera.

The active camera can also be set in the Scene tab of the Properties Editor.

The camera with the solid triangle on top is the active camera.

Warning

The active camera, as well as the layers, can be specific to a given view, or global (locked) to the whole scene.

Render Border

Reference

Mode: All modes

Menu: View ‣ Render Border

Hotkey: Ctrl-B

Title-Img. 4. 9Render Border toggle.

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Link-


tion.html

While in camera view, you can define a sub region to render by drawing out a rectangle within the camera’s frame. Your renders will now be limited to the part of scene visible within the render border. This can be very useful for reducing render times for quick previews on an area of interest.

The border can be disabled by disabling the Border option in the Dimensions panel in the Render tab or by activating the option again.

Note

When Render Border is activated, Sampled Motion Blur will become available to view in the 3D View.

Title-Img. 4. 10 Render border and associated render

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Object Data

Cameras are invisible in renders, so they do not have any material or texture settings. However, they do have Object and Editing setting panels available which are displayed when a camera is the selected (active!) object.





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Camera Lens

Title-Img. 4. 10Camera Lens panel.

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https://docs.blender.org/manual/en/dev/render/blender_render/camera/object_

data.html

The camera lens options control the way 3D objects are represented in a 2D image.

Lens Type

There are three different lens types:

1. Perspective

2. Orthographic

3. Panoramic

Perspective

This matches how you view things in the real-world. Objects in the distance will appear smaller than objects in the foreground, and parallel lines (such as the rails on a railroad) will appear to converge as they get farther away.

https://docs.blender.org/manual/en/dev/render/blender_render/camera/object_data.html



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Title-Img. 4. 11 Render of a train track scene with a Perspective camera.

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Settings which adjust this projection include:

Focal length

Shift

Sensor size

Focal length

The focal length setting controls the amount of zoom, i.e. the amount of the scene which is visible all at once. Longer focal lengths result in a smaller FOV (more zoom), while short focal lengths allow you to see more of the scene at once (larger FOV, less zoom).



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Title-Img. 4. 12 Render of the same scene as above, but with a focal length

of 210mm instead of 35mm.

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Lens Unit

The focal length can be set either in terms of millimeters or the actual Field of View as an angle.

Orthographic

With Orthographic perspective objects always appear at their actual size, regardless of distance. This means that parallel lines appear parallel, and do not converge like they do with Perspective.




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Title-Img. 4. 13 Render from the same camera angle as the previous

examples, but with orthographic perspective.

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Orthographic Scale

This controls the apparent size of objects in the camera.

Note that this is effectively the only setting which applies to orthographic perspective. Since parallel lines do not converge in orthographic mode (no vanishing points), the lens shift settings are equivalent to translating the camera in the 3D View.

Panoramic

Panoramic cameras are only supported in the Cycles render engine.

Shift

The Shift setting allows for the adjustment of vanishing points. Vanishing points refer to the positions to which parallel lines converge. In this example, the most obvious vanishing point is at the end of the railroad.

To see how this works, take the following examples:

Title- Img. 4. 14 Render of a train track scene with a horizontal lens shift of

0.330.

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Title-Img. 4. 15 Render of a train track scene with a rotation of the camera

object instead of a lens shift.

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Notice how the horizontal lines remain perfectly horizontal when using the lens shift, but do get skewed when rotating the camera object.

Using lens shift is equivalent to rendering an image with a larger FOV and cropping it off-center.

Clipping

Set the clipping limits with the Start and End values.

Only objects within the limits are rendered.

For OpenGL display, setting clipping distances to limited values is important to ensure sufficient rasterization precision. Ray tracing renders do not suffer from this issue so much, and as such more extreme values can safely be set.

When Limits in the Display panel is enabled, the clip bounds will be visible as two yellow connected dots on the camera line of sight.






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Camera Preset

Options

Camera Presets

Title-Img. 4.

16Camera Presets panel.

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Sensor size

This setting is an alternative way to control the focal-

length, it is useful to match the camera in Blender to a

physical camera & lens combination, e.g. for motion

tracking.

Depth of Field

Title-Img. 4. 17Camera Depth of Field Panel.

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Real world cameras transmit light through a lens that bends and focuses it onto the sensor. Because of this, objects that are a





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certain distance away are in focus, but objects in front and behind that are blurred.

The area in focus is called the focal point and can be set using either an exact value, or by using the distance between the camera and a chosen object:

Focus Object

Choose an object which will determine the focal point. Linking an object will deactivate the distance parameter. Typically, this is used to give precise control over the position of the focal point, and also allows it to be animated or constrained to another object.

Distance

Sets the distance to the focal point, when no Focus Object is specified. If Limits are enabled, a yellow cross is shown on the camera line of sight at this distance.

Hint

Hover the mouse over the Distance property and press E to

use a special Depth Picker. Then click on a point in the 3D

View to sample the distance from that point to the camera.

High Quality

In order for the viewport to offer an accurate

representation of depth of field, like a render, you must

enable High Quality. Without it, you may notice a

difference in shading.

Viewport F-stop

Controls the real-time focal blur effect used during

sequencer or OpenGL rendering and, when enabled,

camera views in the 3D View. The amount of blur depends

on this setting, along with Focal Length and Sensor Size.

Smaller Viewport F-stop values result in more blur.

Blades

Add a number of polygonal blades to the blur effect, in

order to achieve a bokeh effect in the viewport. To enable

this feature, the blades must be set to at least 3 (3 sides,

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Title-Img. 4. 18The viewport bokeh effect with the blades set to 3.

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Display

Title-Img. 4. 19Camera Display Panel.

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Limits

Shows a line which indicates Start and End Clipping values.





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Mist

Toggles viewing of the mist limits on and off. The limits are shown as two connected white dots on the camera line of sight. The mist limits and other options are set in the World panel, in the Mist section.

Title-Img. 4. 20Camera view displaying safe areas, sensor and name.

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Sensor

Displays a dotted frame in camera view.

Name

Toggle name display on and off in camera view.

Size

Refers to the size of the camera icon in the 3D View. This

setting has no effect on the render output of a camera, and

is only a cosmetic setting. The camera icon can also be

scaled using the standard Scale S transform key.

Passé partout, Alpha

This mode darkens the area outside of the camera’s field of

view, based on the Alpha setting.




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Composition Guides

Composition Guides are available from the menu, which

can help when framing a shot. There are eight types of

guides available:

Center

Adds lines dividing the frame in half vertically and

horizontally.

Center Diagonal

Adds lines connecting opposite corners.

Thirds

Adds lines dividing the frame in thirds vertically and

horizontally.

Golden

Divides the width and height into Golden proportions

(About 0.618 of the size from all sides of the frame).

Golden Triangle A

Draws a diagonal line from the lower-left to upper-right

corners, then adds perpendicular lines that pass through

the top left and bottom right corners.

Golden Triangle B

Same as A, but with the opposite corners.

Harmonious Triangle A

Draws a diagonal line from the lower-left to upper-right

corners, then lines from the top left and bottom right

corners to 0.618 the lengths of the opposite side.

Harmonious Triangle B

Same as A, but with the opposite corners.

Safe Areas

Safe areas are guides used to position elements to ensure that the most important parts of the content can be seen across all screens.

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Different screens have varying amounts of over scan (specially older TV sets). That means that not all content will be visible to all viewers, since parts of the image surrounding the edges are not shown. To work around this problem TV producers defined, two areas where content is guaranteed to be shown: action safe and title safe.

Modern LCD/plasma screens with purely digital signals have no over scan, yet safe areas are still considered best practice and may be legally required for broadcast.

In Blender, safe areas can be set from the Camera and Sequencer views.

Title-Img. 4. 21The Safe areas panel found in the camera properties, and the view

mode of the sequencer.

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Main Safe Areas

Title- Img. 4. 22Red line: Action safe. Green line: Title safe.

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Title Safe

Title safe is also known as Graphics Safe. Place all important information (graphics or text) inside this area to ensure it can be seen by the majority of viewers.

Action Safe

Make sure any significant action or characters in the shot are inside this area. This zone also doubles as a sort of “margin” for the screen which can be used to keep elements from piling up against the edges.

Tip

Legal Standards

Each country sets a legal standard for broadcasting. These include, among other things, specific values for safe areas. Blender defaults for safe areas follow the EBU (European Union) standard. Make sure you are using the correct values when working for broadcast to avoid any trouble.

Center-Cuts

Title- Img. 4. 23Cyan line: action center safe. Blue line: title center safe.

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Center-cuts are a second set of safe areas to ensure content is seen correctly on screens with a different aspect ratio. Old TV sets receiving 16:9 or 21:9 video will cut off the sides. Position content inside the center-cut areas to make sure the most important elements of your composition can still be visible in these screens.

Blender defaults show a 4:3 (square) ratio inside 16:9 (wide-screen).


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Unit summary

Summary

In this Unit, you have learnt how to

Use Lighting Rig to produce photorealistic results with its

physically plausible shading and lighting system.

Work with lights realistically, with shape and falloff.

Produce final quality results, resulting in faster setup and more accurate results.

After learning this Unit, you can download the Open Source Software available on the internet for free of cost to practice the possibilities of creating 3D Objects.

Assignment

Assignment

Use the same Living Room scene created for Block 02, Unit

– 01 Assignment to light with Blender, improvise the same

using Lamps as rigs and render using camera with required

DOF – Depth of Field

Use this key word “photo frame on wall” on www.google.com to collect the reference image to build your lighting reference.





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Assessment

Assessment

1. Describe the use of Light Rigs

2. Explain One-point light rig with appropriate example

3. Explain Two-point light rig with appropriate example

4. Explain Studio light rig with appropriate example

5. Describe Depth of Filed

Objective type Questions

1. You can make the spot wider by increasing spot ____________

2. Studio Light rig is similar to ___________ Light Rig

3. You cannot set lights to only light objects on a layer (True / False)

4. Hard, bright lights actually flatten it and make you squint. Soft

lights allow your eye to focus (True / False)

5. Ambient light illuminates, in a perfectly balanced, Shadeless way,

without casting shadows (True / False)

Resources

Study Skills

While studying this Unit, you can browse the following internet

links for online video tutorials and several books and training

DVDs available in theBlender Storeand on theBlender Cloud.

Links to download 3D Files for practice - Copyright Notice Attribution-NonCommercial-ShareAlike CC BY-NC-SA

1. https://wiki.blender.org/index.php/Doc:2.4/Tutorials/Lig

hting/BSoD

2. https://cloud.blender.org/p/hdri

3. wiki.blender.org






https://cloud.blender.org/p/hdri


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5. archive.org

6. www.blender.org

7. docs.blender.org

Books to refer

8. Blender 2.5 Lighting and Rendering by Aaron W. Powell

9. Read Chapter 7 of the John Blain "Complete Guide to

Blender Graphics" - Lighting and Cameras (pages 131-

136)

10. https://www.lifewire.com/quick-tips-for-interesting-cg-

lighting-2119




Lighting Rigs

Documents

Transcript of Lighting Rigs